5ef1ba7ff5
Summary: A generic rate limiter that can be shared by threads and rocksdb instances. Will use this to smooth out write traffic generated by compaction and flush. This will help us get better p99 behavior on flash storage. Test Plan: unit test output ==== Test RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.374969 KB/sec, elapsed 2002265 request size [1 - 2047], limit 20 KB/sec, actual rate: 20.771242 KB/sec, elapsed 2002139 request size [1 - 4095], limit 40 KB/sec, actual rate: 41.285299 KB/sec, elapsed 2202424 request size [1 - 8191], limit 80 KB/sec, actual rate: 81.371605 KB/sec, elapsed 2402558 request size [1 - 16383], limit 160 KB/sec, actual rate: 162.541268 KB/sec, elapsed 3303500 Reviewers: yhchiang, igor, sdong Reviewed By: sdong Subscribers: leveldb Differential Revision: https://reviews.facebook.net/D19359
81 lines
2.5 KiB
C++
81 lines
2.5 KiB
C++
// Copyright (c) 2014, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#include <limits>
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#include "util/testharness.h"
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#include "util/rate_limiter.h"
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#include "util/random.h"
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#include "rocksdb/env.h"
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namespace rocksdb {
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class RateLimiterTest {
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};
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TEST(RateLimiterTest, StartStop) {
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std::unique_ptr<RateLimiter> limiter(new RateLimiter(100, 100, 10));
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}
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TEST(RateLimiterTest, Rate) {
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auto* env = Env::Default();
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struct Arg {
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Arg(int64_t target_rate, int burst)
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: limiter(new RateLimiter(target_rate, 100 * 1000, 10)),
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request_size(target_rate / 10),
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burst(burst) {}
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std::unique_ptr<RateLimiter> limiter;
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int64_t request_size;
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int burst;
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};
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auto writer = [](void* p) {
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auto* env = Env::Default();
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auto* arg = static_cast<Arg*>(p);
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// Test for 2 seconds
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auto until = env->NowMicros() + 2 * 1000000;
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Random r((uint32_t)(env->NowNanos() %
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std::numeric_limits<uint32_t>::max()));
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while (env->NowMicros() < until) {
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for (int i = 0; i < static_cast<int>(r.Skewed(arg->burst) + 1); ++i) {
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arg->limiter->Request(r.Uniform(arg->request_size - 1) + 1,
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Env::IO_HIGH);
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}
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arg->limiter->Request(r.Uniform(arg->request_size - 1) + 1,
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Env::IO_LOW);
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}
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};
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for (int i = 1; i <= 16; i*=2) {
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int64_t target = i * 1024 * 10;
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Arg arg(target, i / 4 + 1);
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auto start = env->NowMicros();
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for (int t = 0; t < i; ++t) {
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env->StartThread(writer, &arg);
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}
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env->WaitForJoin();
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auto elapsed = env->NowMicros() - start;
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double rate = arg.limiter->GetTotalBytesThrough()
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* 1000000.0 / elapsed;
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fprintf(stderr, "request size [1 - %ld], limit %ld KB/sec, "
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"actual rate: %lf KB/sec, elapsed %.2lf seconds\n",
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arg.request_size - 1, target / 1024, rate / 1024,
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elapsed / 1000000.0);
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ASSERT_GE(rate / target, 0.95);
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ASSERT_LE(rate / target, 1.05);
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}
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}
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} // namespace rocksdb
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int main(int argc, char** argv) {
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return rocksdb::test::RunAllTests();
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}
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