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f79b3d19a7
Summary:
**Context/Summary:**
Previous experience with bugs and flaky tests taught us there exist features in RocksDB vulnerable to race condition caused by acquiring db mutex at a particular timing. This PR aggressively exposes those vulnerable features by injecting spurious wakeup and sleep to cause acquiring db mutex at various timing in order to expose such race condition
**Testing:**
- `COERCE_CONTEXT_SWITCH=1 make -j56 check / make -j56 db_stress` should reveal
- flaky tests caused by db mutex related race condition
- Reverted https://github.com/facebook/rocksdb/pull/9528
- A/B testing on `COMPILE_WITH_TSAN=1 make -j56 listener_test` w/ and w/o `COERCE_CONTEXT_SWITCH=1` followed by `./listener_test --gtest_filter=EventListenerTest.MultiCF --gtest_repeat=10`
- `COERCE_CONTEXT_SWITCH=1` can cause expected test failure (i.e, expose target TSAN data race error) within 10 run while the other couldn't.
- This proves our injection can expose flaky tests caused by db mutex related race condition faster.
- known or new race-condition-type of internal bug by continuously running this PR
- Performance
- High ops-threads time: COERCE_CONTEXT_SWITCH=1 regressed by 4 times slower (2:01.16 vs 0:22.10 elapsed ). This PR will be run as a separate CI job so this regression won't affect any existing job.
```
TEST_TMPDIR=$db /usr/bin/time ./db_stress \
--ops_per_thread=100000 --expected_values_dir=$exp --clear_column_family_one_in=0 \
--write_buffer_size=524288 —target_file_size_base=524288 —ingest_external_file_one_in=100 —compact_files_one_in=1000 —compact_range_one_in=1000
```
- Start-up time: COERCE_CONTEXT_SWITCH=1 didn't regress by 25% (0:01.51 vs 0:01.29 elapsed)
```
TEST_TMPDIR=$db ./db_stress -ops_per_thread=100000000 -expected_values_dir=$exp --clear_column_family_one_in=0 & sleep 120; pkill -9 db_stress
TEST_TMPDIR=$db /usr/bin/time ./db_stress \
--ops_per_thread=1 -reopen=0 --expected_values_dir=$exp --clear_column_family_one_in=0 --destroy_db_initially=0
```
Pull Request resolved: https://github.com/facebook/rocksdb/pull/10291
Reviewed By: ajkr
Differential Revision: D39231182
Pulled By: hx235
fbshipit-source-id: 7ab6695430460e0826727fd8c66679b32b3e44b6
91 lines
2.5 KiB
C++
91 lines
2.5 KiB
C++
// Copyright (c) 2011-present, Facebook, Inc. All rights reserved.
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// This source code is licensed under both the GPLv2 (found in the
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// COPYING file in the root directory) and Apache 2.0 License
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// (found in the LICENSE.Apache file in the root directory).
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#include "monitoring/instrumented_mutex.h"
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#include "monitoring/perf_context_imp.h"
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#include "monitoring/thread_status_util.h"
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#include "rocksdb/system_clock.h"
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#include "test_util/sync_point.h"
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namespace ROCKSDB_NAMESPACE {
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namespace {
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#ifndef NPERF_CONTEXT
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Statistics* stats_for_report(SystemClock* clock, Statistics* stats) {
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if (clock != nullptr && stats != nullptr &&
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stats->get_stats_level() > kExceptTimeForMutex) {
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return stats;
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} else {
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return nullptr;
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}
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}
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#endif // NPERF_CONTEXT
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} // namespace
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void InstrumentedMutex::Lock() {
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PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
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db_mutex_lock_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
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stats_for_report(clock_, stats_), stats_code_);
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LockInternal();
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}
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void InstrumentedMutex::LockInternal() {
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#ifndef NDEBUG
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ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
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#endif
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#ifdef COERCE_CONTEXT_SWITCH
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if (stats_code_ == DB_MUTEX_WAIT_MICROS) {
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thread_local Random rnd(301);
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if (rnd.OneIn(2)) {
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if (bg_cv_) {
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bg_cv_->SignalAll();
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}
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sched_yield();
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} else {
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uint32_t sleep_us = rnd.Uniform(11) * 1000;
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if (bg_cv_) {
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bg_cv_->SignalAll();
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}
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SystemClock::Default()->SleepForMicroseconds(sleep_us);
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}
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}
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#endif
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mutex_.Lock();
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}
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void InstrumentedCondVar::Wait() {
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PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
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db_condition_wait_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
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stats_for_report(clock_, stats_), stats_code_);
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WaitInternal();
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}
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void InstrumentedCondVar::WaitInternal() {
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#ifndef NDEBUG
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ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
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#endif
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cond_.Wait();
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}
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bool InstrumentedCondVar::TimedWait(uint64_t abs_time_us) {
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PERF_CONDITIONAL_TIMER_FOR_MUTEX_GUARD(
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db_condition_wait_nanos, stats_code_ == DB_MUTEX_WAIT_MICROS,
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stats_for_report(clock_, stats_), stats_code_);
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return TimedWaitInternal(abs_time_us);
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}
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bool InstrumentedCondVar::TimedWaitInternal(uint64_t abs_time_us) {
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#ifndef NDEBUG
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ThreadStatusUtil::TEST_StateDelay(ThreadStatus::STATE_MUTEX_WAIT);
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#endif
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TEST_SYNC_POINT_CALLBACK("InstrumentedCondVar::TimedWaitInternal",
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&abs_time_us);
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return cond_.TimedWait(abs_time_us);
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}
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} // namespace ROCKSDB_NAMESPACE
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