Revision 044af85847ff7c75717473328f7e0b3f006d431c authored by Igor Canadi on 05 May 2014, 21:44:57 UTC, committed by Igor Canadi on 05 May 2014, 21:44:57 UTC
1 parent 7984b9b
sync_point.h
// Copyright (c) 2014, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
#pragma once
#include <condition_variable>
#include <mutex>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <vector>
#ifdef NDEBUG
#define TEST_SYNC_POINT(x)
#else
namespace rocksdb {
// This class provides facility to reproduce race conditions deterministically
// in unit tests.
// Developer could specify sync points in the codebase via TEST_SYNC_POINT.
// Each sync point represents a position in the execution stream of a thread.
// In the unit test, 'Happens After' relationship among sync points could be
// setup via SyncPoint::LoadDependency, to reproduce a desired interleave of
// threads execution.
// Refer to (DBTest,TransactionLogIteratorRace), for an exmaple use case.
class SyncPoint {
public:
static SyncPoint* GetInstance();
struct Dependency {
std::string predecessor;
std::string successor;
};
// call once at the beginning of a test to setup the dependency between
// sync points
void LoadDependency(const std::vector<Dependency>& dependencies);
// enable sync point processing (disabled on startup)
void EnableProcessing();
// disable sync point processing
void DisableProcessing();
// remove the execution trace of all sync points
void ClearTrace();
// triggered by TEST_SYNC_POINT, blocking execution until all predecessors
// are executed.
void Process(const std::string& point);
// TODO: it might be useful to provide a function that blocks until all
// sync points are cleared.
private:
bool PredecessorsAllCleared(const std::string& point);
// successor/predecessor map loaded from LoadDependency
std::unordered_map<std::string, std::vector<std::string>> successors_;
std::unordered_map<std::string, std::vector<std::string>> predecessors_;
std::mutex mutex_;
std::condition_variable cv_;
// sync points that have been passed through
std::unordered_set<std::string> cleared_points_;
bool enabled_ = false;
};
} // namespace rocksdb
// Use TEST_SYNC_POINT to specify sync points inside code base.
// Sync points can have happens-after depedency on other sync points,
// configured at runtime via SyncPoint::LoadDependency. This could be
// utilized to re-produce race conditions between threads.
// See TransactionLogIteratorRace in db_test.cc for an example use case.
// TEST_SYNC_POINT is no op in release build.
#define TEST_SYNC_POINT(x) rocksdb::SyncPoint::GetInstance()->Process(x)
#endif // NDEBUG
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