| // Copyright (c) 2011-present, Facebook, Inc. All rights reserved. |
| // This source code is licensed under both the GPLv2 (found in the |
| // COPYING file in the root directory) and Apache 2.0 License |
| // (found in the LICENSE.Apache file in the root directory). |
| // |
| #pragma once |
| #include "db/version_edit.h" |
| #include "util/random.h" |
| |
| namespace rocksdb { |
| static const uint32_t kFileReadSampleRate = 1024; |
| extern bool should_sample_file_read(); |
| extern void sample_file_read_inc(FileMetaData*); |
| |
| inline bool should_sample_file_read() { |
| return (Random::GetTLSInstance()->Next() % kFileReadSampleRate == 307); |
| } |
| |
| inline void sample_file_read_inc(FileMetaData* meta) { |
| meta->stats.num_reads_sampled.fetch_add(kFileReadSampleRate, |
| std::memory_order_relaxed); |
| } |
| } |