4ffa4c9628
Soul's sixth pass (N1): every CallScope destructor wakes every waiter, so without the predicate a poll leaves whenever another host thread makes any call. Every scenario had a single-threaded host, and dropping the predicate survived the whole matrix on both targets. `pollbusy` is a public-API scenario and needs no development seam. A second host thread calls `cultmesh_quic_last_error` every 20 ms for twice the poll's timeout while an idle `poll(1000)` waits. It checks the timing first. It then checks the other thread's call count, so a poll that passed without ever being woken reads as the fixture failing. Three harness entries: - revert: no predicate, `woken` taken from `cv_status`; - loosening: the wait reads what woke it and does not wait again; - loosening: a hand-written loop that restarts the whole timeout on every wake. Its lateness is a function of the input. Each was compiled in and run through every scenario on both targets: - revert and read-what-woke: `pollbusy` returns at 0 ms; - re-arm: `pollbusy` returns at about 3000 ms. The earlier scenarios all stay green under all three. The harness kills all three on both targets. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
865 lines
42 KiB
C++
865 lines
42 KiB
C++
// Scenario runner for the bridge's runtime lifetime rules.
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//
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// This is the one part of the bridge a host cannot check by reading: whether
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// `cultmesh_quic_runtime_close` is safe against host threads that are inside the
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// library when it starts. Everything here drives that path and nothing else. It
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// opens a runtime, parks pollers in `cultmesh_quic_next_event`, closes the
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// runtime underneath them, and asserts what the header promises: every parked
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// poller returns, and none of them touches the runtime after it is gone.
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//
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// It consumes the bridge through include/cultmesh_quic_native.h — the same
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// contract a host has — and nothing else. No MsQuic header, no internals.
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//
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// The failures it exists to catch are not visible in the return values, because
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// a use-after-free is not an error code. Two things make them visible instead:
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// a sanitizer build (ThreadSanitizer for the notify/destroy race, AddressSanitizer
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// for the freed-runtime dereference), and `CULTMESH_QUIC_DEBUG_ASSERTS`, which
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// makes the bridge state the quiesce invariant itself rather than leaving it to
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// be caught by an unlucky thread schedule.
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//
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// cultmesh_quic_native_tests closerace [iterations] [pollers]
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// cultmesh_quic_native_tests holdclose [iterations] [pollers]
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// cultmesh_quic_native_tests polltimeout [iterations]
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// cultmesh_quic_native_tests pollbusy [iterations]
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// cultmesh_quic_native_tests latecall [iterations]
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// cultmesh_quic_native_tests holdtimeout [iterations]
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//
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// `closerace` hunts the race: many pollers, many iterations, and whatever the
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// schedule gives. `holdclose` takes the guessing out of it — the bridge's
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// development seam (section 7 of the header) holds the pollers inside the
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// library until this scenario releases them, and reports how many host calls the
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// bridge actually counted, so the scenario asserts the quiesce instead of
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// assuming its own fixture worked. It needs CULTMESH_QUIC_DEBUG_ASSERTS.
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//
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// In both of those the wait is ended by the close, so the host's timeout governs
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// nothing either of them can see, and a bridge waiting on a constant of its own
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// passes both. `polltimeout` is the one that lets the timeout govern the return
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// and measures it, and `pollbusy` measures it again with the host's other thread
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// calling in throughout, which wakes the wait. `latecall` covers the other half
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// of section 4: a call that races the start of a close is refused rather than
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// counted behind its wait.
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// `holdtimeout` covers the seam's own rule, which nothing else is in a position
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// to see: the hold parks a call the wait woke and not one whose own timeout
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// expired, so the quiesce the hold scenarios assert is the bridge's doing and
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// not the fixture's.
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//
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// Exit code 0 means every assertion held. Anything else, including a sanitizer
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// abort or the bridge's own assertion, is a failure. Under ThreadSanitizer run
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// it with `TSAN_OPTIONS=halt_on_error=1`, or a reported race leaves the exit
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// code to the last thing that set it.
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#include <cultmesh_quic_native.h>
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#if defined(_WIN32)
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#define WIN32_LEAN_AND_MEAN
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#define NOMINMAX
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#include <windows.h>
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#endif
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#include <algorithm>
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#include <array>
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#include <atomic>
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#include <chrono>
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#include <climits>
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#include <cstdio>
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#include <cstdlib>
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#include <cstring>
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#include <string>
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#include <thread>
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#include <vector>
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namespace {
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// Long enough that a poller is still parked when the close begins. The close is
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// what ends the wait; this timeout only bounds the scenario if the close never
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// arrives, which is itself the failure.
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constexpr int32_t kPollTimeoutMs = 5000;
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// A poller asks for a payload buffer, so the close races a `next_event` that has
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// somewhere to copy into rather than one that can only ever return 0.
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constexpr int32_t kPayloadCapacity = 4096;
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int Fail(const std::string& message) {
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std::fprintf(stderr, "FAILED: %s\n", message.c_str());
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return 1;
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}
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// One iteration: `pollers` threads parked in `next_event`, then a close under
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// them. Returns an empty string when every promise held.
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//
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// Each poller makes exactly one blocking call and does not call again. Section 5
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// of the header puts the ordering on the host — no call may *begin* during a
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// close — so a scenario that kept re-entering would be testing a shape the
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// bridge declines to support, and its report would be the harness's own fault.
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// A call already inside the library is the case the quiesce exists for, and that
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// is the one run here.
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std::string CloseRaceOnce(int pollers) {
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void* runtime = nullptr;
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const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
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if (opened != 0 || runtime == nullptr)
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return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
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// Counts threads about to enter the blocking call. The close waits for all of
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// them, so the race is run with the pollers actually inside rather than with
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// threads that have not started yet.
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std::atomic<int> entering{0};
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std::atomic<int> returned{0};
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std::atomic<int> undefined_return{0};
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std::atomic<int> timed_out{0};
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// Set just before the close, and read by each poller as it returns. A poller
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// that is already out by then was never in the race, and a scenario full of
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// those passes without testing anything: this is what catches a bridge whose
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// blocking crossing has stopped blocking.
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std::atomic<bool> closing_started{false};
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std::atomic<int> left_before_the_close{0};
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std::vector<std::thread> threads;
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threads.reserve(static_cast<size_t>(pollers));
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for (int index = 0; index < pollers; ++index) {
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threads.emplace_back([runtime, &entering, &returned, &undefined_return, &timed_out,
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&closing_started, &left_before_the_close] {
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std::vector<uint8_t> payload(static_cast<size_t>(kPayloadCapacity));
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cultmesh_quic_event event{};
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int32_t required = 0;
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entering.fetch_add(1);
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const auto started = std::chrono::steady_clock::now();
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// Parked here when the close arrives. `closing` wakes the wait; the
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// call scope this thread holds is what the close must count out
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// before it frees anything.
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const int32_t result = cultmesh_quic_next_event(
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runtime, kPollTimeoutMs, &event, payload.data(), kPayloadCapacity, &required);
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const auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
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std::chrono::steady_clock::now() - started).count();
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if (result != 0 && result != 1 && result != 2) undefined_return.fetch_add(1);
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// The close is what ends this wait. Sitting out the whole timeout
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// instead means the wake never reached it.
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if (elapsed >= kPollTimeoutMs / 2) timed_out.fetch_add(1);
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if (!closing_started.load()) left_before_the_close.fetch_add(1);
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returned.fetch_add(1);
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});
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}
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while (entering.load() < pollers) std::this_thread::yield();
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// Settle so the pollers are inside the blocking wait rather than on their way
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// to it. A poller that has not entered yet is a call beginning during the
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// close, which is the host's to avoid, not the bridge's to survive.
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std::this_thread::sleep_for(std::chrono::milliseconds(50));
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closing_started.store(true);
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cultmesh_quic_runtime_close(runtime);
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for (auto& thread : threads) thread.join();
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if (left_before_the_close.load() != 0)
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return std::to_string(left_before_the_close.load()) + " of " + std::to_string(pollers) +
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" pollers returned before the close began, so they were never in the race";
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if (undefined_return.load() != 0)
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return std::to_string(undefined_return.load()) + " poller(s) saw a return the header does not define";
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if (timed_out.load() != 0)
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return std::to_string(timed_out.load()) + " of " + std::to_string(pollers) +
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" pollers sat out the timeout instead of being woken by the close";
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if (returned.load() != pollers)
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return std::to_string(returned.load()) + " of " + std::to_string(pollers) + " pollers returned";
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return {};
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}
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// The three timeouts `polltimeout` asks for. More than one, because a single
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// value cannot tell a bridge that honours the host's timeout from one that waits
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// on that same number of its own: a constant has to satisfy every band, and no
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// constant is in two of them.
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//
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// A constant was never the hard case, though, and the numbers are chosen for the
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// waits that are computed from the argument instead. Any mapping that is the
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// identity at every probe passes for free, so each probe is placed to leave one
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// family of ordinary mappings nowhere to be identity:
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//
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// - 15 ms is as small as the OS timer lets a measurement be honest about. A
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// floor — `max(timeout, 100)`, so a polling host cannot spin — and an added
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// constant — `timeout + 100` of grace — are both the whole of the wait here,
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// and nothing larger can see either one under the scheduler's noise.
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// - 200 is the ordinary host poll, and sits between the other two so that a
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// constant cannot satisfy both of its neighbours.
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// - 7300 is long and deliberately not round. A clamp — `min(timeout, 1000)` to
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// notice a shutdown, `min(timeout, 5000)` because five seconds is surely
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// enough — is identity at any probe at or under its ceiling, and a round
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// probe is exactly where somebody's round ceiling sits.
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constexpr int32_t kShortestPollMs = 15;
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constexpr int32_t kShortPollMs = 200;
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constexpr int32_t kLongPollMs = 7300;
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// How much sooner than the timeout a poll may return. A wait may be late; it may
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// not be early, because returning early is exactly what waiting on a shorter
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// duration looks like. This is scheduler granularity, not slack.
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constexpr int kEarlyToleranceMs = 20;
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// How much later than the timeout a single poll may return: an allowance for
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// the scheduler, plus a sixteenth of what was asked for.
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//
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// This is what the probes that look for gross failures use: a constant of the
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// bridge's own, a clamp, a hold that parks a call until it is released, a wait
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// that restarts on every wake. Each of those is wrong by far more than this.
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constexpr int kSchedulerSlackMs = 60;
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constexpr int LateToleranceMs(int32_t timeout_ms) { return kSchedulerSlackMs + timeout_ms / 16; }
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// The 15 ms probe is held to something much tighter, because it is the only
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// place a floor or an added constant shows and a scheduler allowance would hide
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// both. Scheduler delay only ever adds, so the probe is asked
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// `kShortestAttempts` times and the fastest is what is checked: noise has to
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// delay every attempt to fail the bridge, and a floor or offset delays every
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// attempt by construction. Every attempt is still checked for being early.
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constexpr int kShortestAttempts = 10;
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constexpr int kTimerSlackMs = 30;
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// Both allowances were checked against a loaded machine, two busy threads per
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// logical CPU for five rounds of all three timed scenarios, and not a quiet one.
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// Worst overshoot seen, win32-x64 and linux-x64 on 8 logical CPUs:
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// - a single poll: 15 and 41 ms;
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// - the fastest of the 15 ms attempts: 0 and 0 ms.
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// On win32-x64 that needs `MeasureAboveTheLoad` below. At normal priority under
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// the same load a single poll landed up to 127 ms late and the fastest of ten
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// 15 ms attempts up to 87 ms late — Windows makes a woken thread wait out busy
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// threads' time slices — and a tolerance of 45 ms plus a sixteenth failed the
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// unmutated bridge in four rounds of five.
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//
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// The honest limit. Each of these was compiled into the bridge and run through
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// all three timed scenarios on both targets; what survives is not claimed:
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// - an added constant: `timeout + 25` survived and `timeout + 40` died, on the
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// 15 ms probe alone;
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// - a floor: `max(timeout, 40)` survived and `max(timeout, 50)` died, on the
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// 15 ms probe alone and on linux-x64 by 5 ms, so a floor near 50 is a kill
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// that rests on timing;
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// - a scaling: `timeout * 106 / 100` survived and `timeout * 108 / 100` died,
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// on the 7300 ms probe alone;
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// - a clamp: `min(timeout, 7285)` survived and `min(timeout, 7275)` died; a
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// clamp at or above 7300 is the identity at every probe;
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// - a shortening of up to `kEarlyToleranceMs` at any probe.
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// Each run prints its worst overshoot per probe, so the allowances can be
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// rechecked on another machine rather than trusted.
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// The timed scenarios measure the bridge's wait, and on a loaded Windows machine
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// what they would otherwise measure is the scheduler's: a thread woken at the
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// end of its wait queues behind busy threads of equal priority for whole time
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// slices. Raising this process above them takes that out of the measurement,
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// and it needs no privilege on Windows. Linux schedules a woken thread promptly
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// at normal priority under the same load, so nothing is asked of it there.
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void MeasureAboveTheLoad() {
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#if defined(_WIN32)
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SetPriorityClass(GetCurrentProcess(), HIGH_PRIORITY_CLASS);
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#endif
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}
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struct TimedPoll {
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int32_t result;
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long long elapsed_ms;
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};
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TimedPoll PollFor(void* runtime, int32_t timeout_ms) {
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std::vector<uint8_t> payload(static_cast<size_t>(kPayloadCapacity));
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cultmesh_quic_event event{};
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int32_t required = 0;
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const auto started = std::chrono::steady_clock::now();
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const int32_t result = cultmesh_quic_next_event(
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runtime, timeout_ms, &event, payload.data(), kPayloadCapacity, &required);
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const auto elapsed = std::chrono::duration_cast<std::chrono::milliseconds>(
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std::chrono::steady_clock::now() - started).count();
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return {result, elapsed};
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}
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// The host's timeout, and the only thing it is: how long a poll with nothing to
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// deliver stays inside the library. Nothing else here checks it — `closerace`
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// and `holdclose` both end their waits with a close, so in both of them the
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// bridge could wait on any duration at all and every assertion would still hold.
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// A runtime with no listener and no connection has nothing to deliver, so the
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// timeout is what ends this poll, and the elapsed time is what it waited on.
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// The bands every timed poll is held to, and the worst overshoot seen, which is
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// printed so a tolerance can be checked against a machine under load rather than
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// trusted.
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struct Overshoot {
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long long worst_ms = LLONG_MIN;
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void Record(const TimedPoll& poll, int32_t timeout_ms) {
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worst_ms = (std::max)(worst_ms, poll.elapsed_ms - timeout_ms);
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}
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};
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std::string CheckTimedPoll(const TimedPoll& poll, int32_t timeout_ms, int late_tolerance_ms) {
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const std::string asked = "a poll asking for " + std::to_string(timeout_ms) + " ms ";
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if (poll.result != 0)
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return asked + "returned " + std::to_string(poll.result) + ", not the 0 an idle runtime owes it";
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if (poll.elapsed_ms < timeout_ms - kEarlyToleranceMs)
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return asked + "returned after " + std::to_string(poll.elapsed_ms) +
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" ms: the wait ended on some shorter duration than the one it was given";
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if (poll.elapsed_ms > static_cast<long long>(timeout_ms) + late_tolerance_ms)
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return asked + "returned after " + std::to_string(poll.elapsed_ms) +
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" ms: the wait ended on some longer duration than the one it was given";
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return {};
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}
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constexpr std::array<int32_t, 3> kTimedProbesMs{kShortestPollMs, kShortPollMs, kLongPollMs};
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std::string PollTimeoutOnce(std::array<Overshoot, 3>& overshoot) {
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void* runtime = nullptr;
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const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
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if (opened != 0 || runtime == nullptr)
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return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
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std::string failure;
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// The fastest of several, each checked for being early; see kShortestAttempts.
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TimedPoll fastest{0, LLONG_MAX};
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for (int attempt = 0; attempt < kShortestAttempts && failure.empty(); ++attempt) {
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const TimedPoll poll = PollFor(runtime, kShortestPollMs);
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failure = CheckTimedPoll(poll, kShortestPollMs, INT_MAX);
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if (poll.elapsed_ms < fastest.elapsed_ms) fastest = poll;
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}
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if (failure.empty()) {
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overshoot[0].Record(fastest, kShortestPollMs);
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failure = CheckTimedPoll(fastest, kShortestPollMs, kTimerSlackMs);
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}
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for (size_t probe = 1; probe < kTimedProbesMs.size() && failure.empty(); ++probe) {
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const TimedPoll poll = PollFor(runtime, kTimedProbesMs[probe]);
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overshoot[probe].Record(poll, kTimedProbesMs[probe]);
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failure = CheckTimedPoll(poll, kTimedProbesMs[probe], LateToleranceMs(kTimedProbesMs[probe]));
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}
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cultmesh_quic_runtime_close(runtime);
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return failure;
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}
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int PollTimeout(int iterations) {
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MeasureAboveTheLoad();
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std::array<Overshoot, 3> overshoot{};
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for (int iteration = 0; iteration < iterations; ++iteration) {
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const std::string failure = PollTimeoutOnce(overshoot);
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if (!failure.empty())
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return Fail("polltimeout iteration " + std::to_string(iteration) + ": " + failure);
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}
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std::printf("polltimeout %dx: ok (worst overshoot %lld ms at %d best of %d, %lld ms at %d, %lld ms at %d)\n",
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iterations, overshoot[0].worst_ms, kTimedProbesMs[0], kShortestAttempts, overshoot[1].worst_ms, kTimedProbesMs[1],
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overshoot[2].worst_ms, kTimedProbesMs[2]);
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return 0;
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}
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// How long `pollbusy`'s poll asks for, and how often the host's other thread
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|
// calls into the library while it waits.
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constexpr int32_t kBusyPollMs = 1000;
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constexpr int kBusyCallEveryMs = 20;
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|
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// The same rule as `polltimeout` — a poll with nothing to deliver stays for its
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// timeout — for a host with more than one thread, which is every real host: one
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// thread polls, another sends, shuts streams down, reads the last error.
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//
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// Every host call leaves through a scope that wakes every waiter on the
|
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// runtime's condition variable, because that is how the close learns a call has
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// left. So a poll is woken each time any other thread makes any call, and what
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// keeps it inside is the wait's predicate: nothing queued and no close means
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// wait again, for the rest of the time the host asked for. With one host thread
|
|
// nothing else ever calls during the wait, and the predicate could be deleted
|
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// with every other scenario still green.
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//
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// The other thread keeps calling for twice the poll's timeout and then stops,
|
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// so a wait that restarts its whole timeout on every wake is seen as late
|
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// rather than hanging the scenario.
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std::string PollBusyOnce(Overshoot& overshoot) {
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void* runtime = nullptr;
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const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
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if (opened != 0 || runtime == nullptr)
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return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
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|
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std::atomic<int> calls{0};
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std::atomic<int> refused{0};
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std::thread other([runtime, &calls, &refused] {
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const auto until = std::chrono::steady_clock::now() + std::chrono::milliseconds(2 * kBusyPollMs);
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std::array<char, 256> message{};
|
|
while (std::chrono::steady_clock::now() < until) {
|
|
if (cultmesh_quic_last_error(runtime, message.data(), static_cast<int32_t>(message.size())) < 0)
|
|
refused.fetch_add(1);
|
|
calls.fetch_add(1);
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(kBusyCallEveryMs));
|
|
}
|
|
});
|
|
|
|
const TimedPoll poll = PollFor(runtime, kBusyPollMs);
|
|
const int calls_during = calls.load();
|
|
other.join();
|
|
cultmesh_quic_runtime_close(runtime);
|
|
|
|
overshoot.Record(poll, kBusyPollMs);
|
|
if (refused.load() != 0)
|
|
return std::to_string(refused.load()) + " call(s) from the host's other thread were refused "
|
|
"by a runtime that was not closing";
|
|
// The timing first: a poll that left on the first wake returns before the
|
|
// other thread has had time to make many calls, and that is the bridge
|
|
// failing, not the fixture.
|
|
const std::string failure = CheckTimedPoll(poll, kBusyPollMs, LateToleranceMs(kBusyPollMs));
|
|
if (!failure.empty()) return failure + ", while the host's other thread was calling in";
|
|
// A poll that passed with fewer calls than this was never woken, and passed
|
|
// because the fixture did nothing rather than because the bridge held.
|
|
if (calls_during < 3)
|
|
return "the host's other thread made " + std::to_string(calls_during) +
|
|
" call(s) during the poll, so nothing woke it";
|
|
return {};
|
|
}
|
|
|
|
int PollBusy(int iterations) {
|
|
MeasureAboveTheLoad();
|
|
Overshoot overshoot{};
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = PollBusyOnce(overshoot);
|
|
if (!failure.empty())
|
|
return Fail("pollbusy iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("pollbusy %dx: ok (worst overshoot %lld ms at %d)\n", iterations, overshoot.worst_ms,
|
|
kBusyPollMs);
|
|
return 0;
|
|
}
|
|
|
|
// Nothing listens on the discard port, so a connection to it fails and the
|
|
// bridge says why. That reason is the payload this scenario needs, and reaching
|
|
// it takes no listener, no credential and no established connection.
|
|
constexpr uint16_t kClosedPort = 9;
|
|
|
|
// How long the failure is given to arrive. The loopback refusal is immediate;
|
|
// if the refusal is swallowed instead, MsQuic's own handshake timeout ends the
|
|
// connection at 10 seconds and event 4 still arrives, so this only bounds a
|
|
// bridge that reports nothing at all.
|
|
constexpr int kEventDeadlineMs = 20000;
|
|
|
|
// The bridge writes its own reason sentences and every one of them starts here.
|
|
// Checking the bytes, and not only the length, is what separates a payload
|
|
// copied out of the queued event from one copied out of an event that was popped
|
|
// first: the second reads freed memory, which does not spell this.
|
|
constexpr char kReasonPrefix[] = "CultMesh QUIC connection";
|
|
|
|
// The two-phase poll, which is the shape every host uses to size its buffer:
|
|
// ask with nothing, be told what it needs, ask again. What makes it work is that
|
|
// the refusal consumes nothing — the event is still queued, payload and all,
|
|
// after a return of 2 — and that the copy happens before the event is popped.
|
|
// Both are section 6 of the header, and nothing committed reached either.
|
|
std::string PayloadFitOnce() {
|
|
void* runtime = nullptr;
|
|
const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
|
|
if (opened != 0 || runtime == nullptr)
|
|
return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
|
|
|
|
std::string failure;
|
|
uint64_t connection_id = 0;
|
|
const int32_t connecting =
|
|
cultmesh_quic_connection_open(runtime, "127.0.0.1", kClosedPort, &connection_id);
|
|
if (connecting != 0) {
|
|
cultmesh_quic_runtime_close(runtime);
|
|
return "cultmesh_quic_connection_open returned " + std::to_string(connecting);
|
|
}
|
|
|
|
// An out parameter the bridge must not write on a refusal, filled with
|
|
// something the bridge never writes so that a write is visible.
|
|
cultmesh_quic_event poisoned{};
|
|
std::memset(&poisoned, 0xab, sizeof(poisoned));
|
|
cultmesh_quic_event event = poisoned;
|
|
int32_t required = 0;
|
|
int32_t result = 0;
|
|
|
|
// Ask with no room at all until the event carrying the failure reason
|
|
// arrives. An event with no payload fits in nothing, so it is delivered and
|
|
// polled past rather than mistaken for this one.
|
|
const auto deadline = std::chrono::steady_clock::now() + std::chrono::milliseconds(kEventDeadlineMs);
|
|
for (;;) {
|
|
event = poisoned;
|
|
required = 0;
|
|
result = cultmesh_quic_next_event(runtime, 250, &event, nullptr, 0, &required);
|
|
if (result == 2 && required > 0) break;
|
|
if (result < 0) {
|
|
failure = "cultmesh_quic_next_event returned " + std::to_string(result);
|
|
break;
|
|
}
|
|
if (std::chrono::steady_clock::now() >= deadline) {
|
|
failure = "no event carrying a payload arrived within " +
|
|
std::to_string(kEventDeadlineMs) + " ms of a connection to a closed port";
|
|
break;
|
|
}
|
|
}
|
|
|
|
if (failure.empty() && std::memcmp(&event, &poisoned, sizeof(event)) != 0)
|
|
failure = "the refusal wrote to *out_event, which the header says it leaves alone";
|
|
|
|
// Again, with the same empty buffer: a refusal that consumed the event
|
|
// leaves nothing to find the second time.
|
|
if (failure.empty()) {
|
|
cultmesh_quic_event again = poisoned;
|
|
int32_t required_again = 0;
|
|
const int32_t second = cultmesh_quic_next_event(runtime, 0, &again, nullptr, 0, &required_again);
|
|
if (second != 2 || required_again != required)
|
|
failure = "the second ask returned " + std::to_string(second) + " needing " +
|
|
std::to_string(required_again) + ", not the 2 needing " + std::to_string(required) +
|
|
" the first one did: the refusal consumed the event";
|
|
}
|
|
|
|
// And with room, which is where the copy happens. The tail beyond the
|
|
// payload is written too, so a copy that ran past what it was told to write
|
|
// is visible.
|
|
if (failure.empty()) {
|
|
constexpr uint8_t kTail = 0x5a;
|
|
std::vector<uint8_t> payload(static_cast<size_t>(required) + 16, kTail);
|
|
cultmesh_quic_event delivered = poisoned;
|
|
int32_t required_delivered = 0;
|
|
const int32_t third = cultmesh_quic_next_event(
|
|
runtime, 0, &delivered, payload.data(), static_cast<int32_t>(payload.size()),
|
|
&required_delivered);
|
|
const std::string reason(reinterpret_cast<const char*>(payload.data()),
|
|
static_cast<size_t>(required));
|
|
if (third != 1 || required_delivered != required)
|
|
failure = "the ask with room returned " + std::to_string(third) + " needing " +
|
|
std::to_string(required_delivered) + ", not the 1 needing " +
|
|
std::to_string(required) + " the refusal promised";
|
|
else if (delivered.type != CULTMESH_QUIC_EVENT_CONNECTION_SHUTDOWN ||
|
|
delivered.connection_id != connection_id ||
|
|
delivered.payload_length != required)
|
|
failure = "the delivered event was type " + std::to_string(delivered.type) +
|
|
" on connection " + std::to_string(delivered.connection_id) + " carrying " +
|
|
std::to_string(delivered.payload_length) + " byte(s), not the failed connection's own";
|
|
else if (reason.rfind(kReasonPrefix, 0) != 0)
|
|
failure = "the payload delivered was '" + reason + "', not a reason this bridge writes";
|
|
else if (payload[static_cast<size_t>(required)] != kTail)
|
|
failure = "the copy wrote past the " + std::to_string(required) + " bytes it reported";
|
|
}
|
|
|
|
// Consumed now, and only now.
|
|
if (failure.empty()) {
|
|
cultmesh_quic_event emptied = poisoned;
|
|
int32_t required_emptied = 0;
|
|
const int32_t fourth =
|
|
cultmesh_quic_next_event(runtime, 0, &emptied, nullptr, 0, &required_emptied);
|
|
if (fourth != 0)
|
|
failure = "the event was still queued after being delivered: a further ask returned " +
|
|
std::to_string(fourth);
|
|
}
|
|
|
|
cultmesh_quic_runtime_close(runtime);
|
|
return failure;
|
|
}
|
|
|
|
int PayloadFit(int iterations) {
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = PayloadFitOnce();
|
|
if (!failure.empty())
|
|
return Fail("payloadfit iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("payloadfit %dx: ok\n", iterations);
|
|
return 0;
|
|
}
|
|
|
|
#if defined(CULTMESH_QUIC_DEBUG_ASSERTS)
|
|
|
|
// How long a poll that does not block is given to prove it by returning, after
|
|
// the calls have been counted and before the close begins. A bridge whose
|
|
// blocking wait no longer blocks has emptied itself of host calls by the time
|
|
// the close starts, and `calls_at_close` then says 0.
|
|
constexpr int kSettleMs = 100;
|
|
|
|
// How long the close is required to stay inside `cultmesh_quic_runtime_close`
|
|
// while the pollers are held. The held calls are what it is waiting for, and
|
|
// nothing releases them until this elapses, so a close that returns first gave
|
|
// up on a call that was still inside. This bounds what the scenario can see: a
|
|
// close that waits for longer than this and then gives up is not distinguished
|
|
// from one that waits properly, which is the honest limit of the check.
|
|
constexpr int kHeldWindowMs = 500;
|
|
|
|
// How long the pollers are given to be counted inside the library before the
|
|
// close begins. Reaching `pollers` is the normal path; the deadline only stops
|
|
// a bridge that never counts them from hanging the scenario.
|
|
constexpr int kCountedDeadlineMs = 2000;
|
|
|
|
// One iteration of the quiesce itself, with the guesswork taken out: the pollers
|
|
// are held inside the library by the bridge's own development seam until this
|
|
// scenario lets them go, and the bridge says how many calls it counted rather
|
|
// than the scenario assuming the schedule put them there.
|
|
//
|
|
// Three promises, and a mutation that breaks any one of them is seen here:
|
|
// - the calls are counted (`peak`), so a blocking crossing outside a call scope
|
|
// is not merely uncounted-but-lucky, it reads as zero;
|
|
// - they were still counted when the close began its wait (`calls_at_close`),
|
|
// so a poll that stopped blocking cannot leave the scenario testing an empty
|
|
// library;
|
|
// - the close did not return while they were held, so a wait that gives up
|
|
// after any interval shorter than the hold is not a wait.
|
|
std::string HoldCloseOnce(int pollers) {
|
|
cultmesh_quic_debug_hold_calls(1);
|
|
void* runtime = nullptr;
|
|
const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
|
|
if (opened != 0 || runtime == nullptr) {
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
|
|
}
|
|
|
|
std::atomic<int> returned{0};
|
|
std::atomic<int> undefined_return{0};
|
|
std::vector<std::thread> threads;
|
|
threads.reserve(static_cast<size_t>(pollers));
|
|
for (int index = 0; index < pollers; ++index) {
|
|
threads.emplace_back([runtime, &returned, &undefined_return] {
|
|
std::vector<uint8_t> payload(static_cast<size_t>(kPayloadCapacity));
|
|
cultmesh_quic_event event{};
|
|
int32_t required = 0;
|
|
const int32_t result = cultmesh_quic_next_event(
|
|
runtime, kPollTimeoutMs, &event, payload.data(), kPayloadCapacity, &required);
|
|
if (result != 0 && result != 1 && result != 2) undefined_return.fetch_add(1);
|
|
returned.fetch_add(1);
|
|
});
|
|
}
|
|
|
|
const auto counted_deadline =
|
|
std::chrono::steady_clock::now() + std::chrono::milliseconds(kCountedDeadlineMs);
|
|
while (cultmesh_quic_debug_peak_calls() < pollers &&
|
|
std::chrono::steady_clock::now() < counted_deadline)
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(1));
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(kSettleMs));
|
|
|
|
std::atomic<bool> closed{false};
|
|
std::thread closer([runtime, &closed] {
|
|
cultmesh_quic_runtime_close(runtime);
|
|
closed.store(true);
|
|
});
|
|
const auto held_until =
|
|
std::chrono::steady_clock::now() + std::chrono::milliseconds(kHeldWindowMs);
|
|
while (!closed.load() && std::chrono::steady_clock::now() < held_until)
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(5));
|
|
|
|
const bool closed_while_held = closed.load();
|
|
const int32_t peak = cultmesh_quic_debug_peak_calls();
|
|
const int32_t at_close = cultmesh_quic_debug_calls_at_close();
|
|
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
closer.join();
|
|
for (auto& thread : threads) thread.join();
|
|
|
|
if (peak != pollers)
|
|
return "the library's peak count of host calls inside it was " + std::to_string(peak) + ", not " +
|
|
std::to_string(pollers) + ": either the blocking crossing is not inside a call scope, or it " +
|
|
"did not block long enough for the pollers to be inside it together";
|
|
if (at_close != pollers)
|
|
return "the close began its wait with " + std::to_string(at_close) +
|
|
" host call(s) counted inside, not " + std::to_string(pollers) +
|
|
"; the pollers were not inside the library when the close started";
|
|
if (closed_while_held)
|
|
return "the close returned while " + std::to_string(pollers) +
|
|
" host call(s) were still held inside the library";
|
|
if (undefined_return.load() != 0)
|
|
return std::to_string(undefined_return.load()) + " poller(s) saw a return the header does not define";
|
|
if (returned.load() != pollers)
|
|
return std::to_string(returned.load()) + " of " + std::to_string(pollers) + " pollers returned";
|
|
return {};
|
|
}
|
|
|
|
// One iteration of the other half of section 4: a call made while a close is
|
|
// running is refused, and is not counted behind the close's wait.
|
|
//
|
|
// The prohibition is the host's — no call may begin after the close starts — and
|
|
// the bridge does not make it optional. What it does do is refuse the call that
|
|
// races the start, and that refusal is load-bearing rather than courteous: a
|
|
// call admitted after the closer has begun increments the in-flight count behind
|
|
// a wait that has already read it, and the wait can then be left waiting on a
|
|
// count that reaches zero only when the late caller happens to leave.
|
|
//
|
|
// The seam is what makes the window wide enough to aim at: a held poller keeps
|
|
// the close inside its wait for as long as this scenario wants it there.
|
|
std::string LateCallOnce() {
|
|
cultmesh_quic_debug_hold_calls(1);
|
|
void* runtime = nullptr;
|
|
const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
|
|
if (opened != 0 || runtime == nullptr) {
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
|
|
}
|
|
|
|
std::thread poller([runtime] {
|
|
std::vector<uint8_t> payload(static_cast<size_t>(kPayloadCapacity));
|
|
cultmesh_quic_event event{};
|
|
int32_t required = 0;
|
|
cultmesh_quic_next_event(
|
|
runtime, kPollTimeoutMs, &event, payload.data(), kPayloadCapacity, &required);
|
|
});
|
|
|
|
const auto counted_deadline =
|
|
std::chrono::steady_clock::now() + std::chrono::milliseconds(kCountedDeadlineMs);
|
|
while (cultmesh_quic_debug_peak_calls() < 1 &&
|
|
std::chrono::steady_clock::now() < counted_deadline)
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(1));
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(kSettleMs));
|
|
|
|
std::thread closer([runtime] { cultmesh_quic_runtime_close(runtime); });
|
|
// The close has begun its wait once it has read the count, and the held
|
|
// poller is what keeps it there.
|
|
const auto started_deadline =
|
|
std::chrono::steady_clock::now() + std::chrono::milliseconds(kCountedDeadlineMs);
|
|
while (cultmesh_quic_debug_calls_at_close() < 0 &&
|
|
std::chrono::steady_clock::now() < started_deadline)
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(1));
|
|
const int32_t at_close = cultmesh_quic_debug_calls_at_close();
|
|
|
|
// Two calls, from a thread of their own so that a bridge which admits them
|
|
// cannot park this one: one that does not block, and then the blocking
|
|
// crossing. That order, because a bridge that admits the blocking one parks
|
|
// it inside the library until the hold is released, and a call made after
|
|
// that would be racing the teardown rather than the wait.
|
|
std::atomic<int32_t> late_poll{0};
|
|
std::atomic<int32_t> late_error{0};
|
|
std::thread late([runtime, &late_poll, &late_error] {
|
|
std::array<char, 256> message{};
|
|
late_error.store(cultmesh_quic_last_error(runtime, message.data(),
|
|
static_cast<int32_t>(message.size())));
|
|
std::vector<uint8_t> payload(static_cast<size_t>(kPayloadCapacity));
|
|
cultmesh_quic_event event{};
|
|
int32_t required = 0;
|
|
late_poll.store(cultmesh_quic_next_event(
|
|
runtime, kPollTimeoutMs, &event, payload.data(), kPayloadCapacity, &required));
|
|
});
|
|
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(kSettleMs));
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
late.join();
|
|
closer.join();
|
|
poller.join();
|
|
|
|
if (at_close < 1)
|
|
return "the close did not begin its wait with the poller counted inside, so nothing held it "
|
|
"open for a call to race";
|
|
if (late_poll.load() != -1)
|
|
return "cultmesh_quic_next_event returned " + std::to_string(late_poll.load()) +
|
|
" to a call made during the close, not the -1 that refuses it";
|
|
if (late_error.load() != -1)
|
|
return "cultmesh_quic_last_error returned " + std::to_string(late_error.load()) +
|
|
" to a call made during the close, not the -1 that refuses it";
|
|
return {};
|
|
}
|
|
|
|
// How long `holdtimeout`'s poll asks for, and how long the hold stays armed
|
|
// under it. The gap between them is the whole measurement: a poll the hold
|
|
// parks leaves when the hold is released, so its elapsed time lands at the
|
|
// second number instead of the first.
|
|
constexpr int32_t kHeldTimeoutPollMs = 150;
|
|
constexpr int kHoldArmedMs = 800;
|
|
|
|
// The seam's own rule, and the only scenario that can see it: the hold parks a
|
|
// call the wait woke, and not one whose own timeout expired.
|
|
//
|
|
// Everything else that arms the hold parks a woken call, so the guard governs
|
|
// nothing either of them observes — the timeout scenario never arms the hold,
|
|
// and the hold scenarios never let a timeout expire, so nothing was ever in
|
|
// both states at once and the guard could be deleted with every scenario still
|
|
// green. This puts one call in both states: the hold is armed, and the runtime
|
|
// is idle, so the wait ends on the timeout and the call is on its way out.
|
|
//
|
|
// It matters because a scenario that parked such a call would then report the
|
|
// bridge keeping a host call inside the library when what kept it was the
|
|
// fixture — the quiesce numbers `holdclose` asserts would be the seam's, not
|
|
// the bridge's.
|
|
std::string HoldTimeoutOnce() {
|
|
cultmesh_quic_debug_hold_calls(1);
|
|
void* runtime = nullptr;
|
|
const int32_t opened = cultmesh_quic_runtime_open("cultmesh-quic-native-tests", &runtime);
|
|
if (opened != 0 || runtime == nullptr) {
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
return "cultmesh_quic_runtime_open returned " + std::to_string(opened);
|
|
}
|
|
|
|
// On a thread of its own, because a parked call does not come back until the
|
|
// release below and this thread is what releases it.
|
|
TimedPoll poll{};
|
|
std::thread poller([runtime, &poll] { poll = PollFor(runtime, kHeldTimeoutPollMs); });
|
|
|
|
std::this_thread::sleep_for(std::chrono::milliseconds(kHoldArmedMs));
|
|
cultmesh_quic_debug_hold_calls(0);
|
|
poller.join();
|
|
cultmesh_quic_runtime_close(runtime);
|
|
|
|
if (poll.result != 0)
|
|
return "a poll ended by its own timeout returned " + std::to_string(poll.result) +
|
|
", not the 0 an idle runtime owes it";
|
|
if (poll.elapsed_ms < kHeldTimeoutPollMs - kEarlyToleranceMs)
|
|
return "a poll asking for " + std::to_string(kHeldTimeoutPollMs) + " ms returned after " +
|
|
std::to_string(poll.elapsed_ms) + " ms, so the fixture never let its timeout run out";
|
|
if (poll.elapsed_ms > kHeldTimeoutPollMs + LateToleranceMs(kHeldTimeoutPollMs))
|
|
return "a poll asking for " + std::to_string(kHeldTimeoutPollMs) + " ms returned after " +
|
|
std::to_string(poll.elapsed_ms) + " ms: the hold parked a call its own timeout had "
|
|
"already ended, and it left when the hold did";
|
|
return {};
|
|
}
|
|
|
|
int HoldTimeout(int iterations) {
|
|
MeasureAboveTheLoad();
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = HoldTimeoutOnce();
|
|
if (!failure.empty())
|
|
return Fail("holdtimeout iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("holdtimeout %dx: ok\n", iterations);
|
|
return 0;
|
|
}
|
|
|
|
int LateCall(int iterations) {
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = LateCallOnce();
|
|
if (!failure.empty())
|
|
return Fail("latecall iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("latecall %dx: ok\n", iterations);
|
|
return 0;
|
|
}
|
|
|
|
int HoldClose(int iterations, int pollers) {
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = HoldCloseOnce(pollers);
|
|
if (!failure.empty())
|
|
return Fail("holdclose iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("holdclose %dx%d: ok\n", iterations, pollers);
|
|
return 0;
|
|
}
|
|
|
|
#endif // CULTMESH_QUIC_DEBUG_ASSERTS
|
|
|
|
int CloseRace(int iterations, int pollers) {
|
|
for (int iteration = 0; iteration < iterations; ++iteration) {
|
|
const std::string failure = CloseRaceOnce(pollers);
|
|
if (!failure.empty())
|
|
return Fail("closerace iteration " + std::to_string(iteration) + ": " + failure);
|
|
}
|
|
std::printf("closerace %dx%d: ok\n", iterations, pollers);
|
|
return 0;
|
|
}
|
|
|
|
} // namespace
|
|
|
|
int main(int argc, char** argv) {
|
|
if (argc < 2) {
|
|
std::fprintf(stderr,
|
|
"usage: %s closerace|holdclose|holdtimeout|polltimeout|pollbusy|payloadfit|latecall "
|
|
"[iterations] [pollers]\n",
|
|
argv[0]);
|
|
return 2;
|
|
}
|
|
const std::string scenario = argv[1];
|
|
const int iterations = argc > 2 ? std::atoi(argv[2]) : 20;
|
|
const int pollers = argc > 3 ? std::atoi(argv[3]) : 256;
|
|
if (iterations <= 0 || pollers <= 0) {
|
|
std::fprintf(stderr, "%s needs a positive iteration and poller count\n", scenario.c_str());
|
|
return 2;
|
|
}
|
|
if (scenario == "closerace") return CloseRace(iterations, pollers);
|
|
if (scenario == "polltimeout") return PollTimeout(iterations);
|
|
if (scenario == "pollbusy") return PollBusy(iterations);
|
|
if (scenario == "payloadfit") return PayloadFit(iterations);
|
|
if (scenario == "holdclose" || scenario == "latecall" || scenario == "holdtimeout") {
|
|
#if defined(CULTMESH_QUIC_DEBUG_ASSERTS)
|
|
if (scenario == "latecall") return LateCall(iterations);
|
|
if (scenario == "holdtimeout") return HoldTimeout(iterations);
|
|
return HoldClose(iterations, pollers);
|
|
#else
|
|
std::fprintf(stderr,
|
|
"%s needs the development seam: configure with "
|
|
"-DCULTMESH_QUIC_DEBUG_ASSERTS=ON\n", scenario.c_str());
|
|
return 2;
|
|
#endif
|
|
}
|
|
std::fprintf(stderr, "unknown scenario '%s'\n", scenario.c_str());
|
|
return 2;
|
|
}
|