Revision 33323f21117e5bb8cf72569302f109aabb387bb9 authored by Mark Callaghan on 14 September 2012, 19:35:02 UTC, committed by Mark Callaghan on 14 September 2012, 23:43:50 UTC
Summary: Reads via mmap on concurrent workloads are much slower than pread. For example on a 24-core server with storage that can do 100k IOPS or more I can get no more than 10k IOPS with mmap reads and 32+ threads. Test Plan: db_bench benchmarks Reviewers: dhruba, heyongqiang Reviewed By: heyongqiang Differential Revision: https://reviews.facebook.net/D5433
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mutexlock.h
// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file. See the AUTHORS file for names of contributors.
#ifndef STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
#define STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
#include "port/port.h"
namespace leveldb {
// Helper class that locks a mutex on construction and unlocks the mutex when
// the destructor of the MutexLock object is invoked.
//
// Typical usage:
//
// void MyClass::MyMethod() {
// MutexLock l(&mu_); // mu_ is an instance variable
// ... some complex code, possibly with multiple return paths ...
// }
class MutexLock {
public:
explicit MutexLock(port::Mutex *mu) : mu_(mu) {
this->mu_->Lock();
}
~MutexLock() { this->mu_->Unlock(); }
private:
port::Mutex *const mu_;
// No copying allowed
MutexLock(const MutexLock&);
void operator=(const MutexLock&);
};
} // namespace leveldb
#endif // STORAGE_LEVELDB_UTIL_MUTEXLOCK_H_
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