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// 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).
//
// 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.
#include "util/rate_limiter.h"
#include <chrono>
#include <cinttypes>
#include <limits>
#include "db/db_test_util.h"
#include "rocksdb/env.h"
#include "test_util/sync_point.h"
#include "test_util/testharness.h"
#include "util/random.h"
namespace ROCKSDB_NAMESPACE {
// TODO(yhchiang): the rate will not be accurate when we run test in parallel.
class RateLimiterTest : public testing::Test {};
TEST_F(RateLimiterTest, OverflowRate) {
GenericRateLimiter limiter(port::kMaxInt64, 1000, 10,
RateLimiter::Mode::kWritesOnly, Env::Default(),
false /* auto_tuned */);
ASSERT_GT(limiter.GetSingleBurstBytes(), 1000000000ll);
}
TEST_F(RateLimiterTest, StartStop) {
std::unique_ptr<RateLimiter> limiter(NewGenericRateLimiter(100, 100, 10));
}
TEST_F(RateLimiterTest, Modes) {
for (auto mode : {RateLimiter::Mode::kWritesOnly,
RateLimiter::Mode::kReadsOnly, RateLimiter::Mode::kAllIo}) {
GenericRateLimiter limiter(
2000 /* rate_bytes_per_sec */, 1000 * 1000 /* refill_period_us */,
10 /* fairness */, mode, Env::Default(), false /* auto_tuned */);
limiter.Request(1000 /* bytes */, Env::IO_HIGH, nullptr /* stats */,
RateLimiter::OpType::kRead);
if (mode == RateLimiter::Mode::kWritesOnly) {
ASSERT_EQ(0, limiter.GetTotalBytesThrough(Env::IO_HIGH));
} else {
ASSERT_EQ(1000, limiter.GetTotalBytesThrough(Env::IO_HIGH));
}
limiter.Request(1000 /* bytes */, Env::IO_HIGH, nullptr /* stats */,
RateLimiter::OpType::kWrite);
if (mode == RateLimiter::Mode::kAllIo) {
ASSERT_EQ(2000, limiter.GetTotalBytesThrough(Env::IO_HIGH));
} else {
ASSERT_EQ(1000, limiter.GetTotalBytesThrough(Env::IO_HIGH));
}
}
}
#if !(defined(TRAVIS) && defined(OS_MACOSX))
TEST_F(RateLimiterTest, Rate) {
auto* env = Env::Default();
struct Arg {
Arg(int32_t _target_rate, int _burst)
: limiter(NewGenericRateLimiter(_target_rate, 100 * 1000, 10)),
request_size(_target_rate / 10),
burst(_burst) {}
std::unique_ptr<RateLimiter> limiter;
int32_t request_size;
int burst;
};
auto writer = [](void* p) {
auto* thread_env = Env::Default();
auto* arg = static_cast<Arg*>(p);
// Test for 2 seconds
auto until = thread_env->NowMicros() + 2 * 1000000;
Random r((uint32_t)(thread_env->NowNanos() %
std::numeric_limits<uint32_t>::max()));
while (thread_env->NowMicros() < until) {
for (int i = 0; i < static_cast<int>(r.Skewed(arg->burst) + 1); ++i) {
arg->limiter->Request(r.Uniform(arg->request_size - 1) + 1,
Env::IO_HIGH, nullptr /* stats */,
RateLimiter::OpType::kWrite);
}
arg->limiter->Request(r.Uniform(arg->request_size - 1) + 1, Env::IO_LOW,
nullptr /* stats */, RateLimiter::OpType::kWrite);
}
};
for (int i = 1; i <= 16; i *= 2) {
int32_t target = i * 1024 * 10;
Arg arg(target, i / 4 + 1);
int64_t old_total_bytes_through = 0;
for (int iter = 1; iter <= 2; ++iter) {
// second iteration changes the target dynamically
if (iter == 2) {
target *= 2;
arg.limiter->SetBytesPerSecond(target);
}
auto start = env->NowMicros();
for (int t = 0; t < i; ++t) {
env->StartThread(writer, &arg);
}
env->WaitForJoin();
auto elapsed = env->NowMicros() - start;
double rate =
(arg.limiter->GetTotalBytesThrough() - old_total_bytes_through) *
1000000.0 / elapsed;
old_total_bytes_through = arg.limiter->GetTotalBytesThrough();
fprintf(stderr,
"request size [1 - %" PRIi32 "], limit %" PRIi32
" KB/sec, actual rate: %lf KB/sec, elapsed %.2lf seconds\n",
arg.request_size - 1, target / 1024, rate / 1024,
elapsed / 1000000.0);
ASSERT_GE(rate / target, 0.80);
ASSERT_LE(rate / target, 1.25);
}
}
}
#endif
TEST_F(RateLimiterTest, LimitChangeTest) {
// starvation test when limit changes to a smaller value
int64_t refill_period = 1000 * 1000;
auto* env = Env::Default();
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
struct Arg {
Arg(int32_t _request_size, Env::IOPriority _pri,
std::shared_ptr<RateLimiter> _limiter)
: request_size(_request_size), pri(_pri), limiter(_limiter) {}
int32_t request_size;
Env::IOPriority pri;
std::shared_ptr<RateLimiter> limiter;
};
auto writer = [](void* p) {
auto* arg = static_cast<Arg*>(p);
arg->limiter->Request(arg->request_size, arg->pri, nullptr /* stats */,
RateLimiter::OpType::kWrite);
};
for (uint32_t i = 1; i <= 16; i <<= 1) {
int32_t target = i * 1024 * 10;
// refill per second
for (int iter = 0; iter < 2; iter++) {
std::shared_ptr<RateLimiter> limiter =
std::make_shared<GenericRateLimiter>(
target, refill_period, 10, RateLimiter::Mode::kWritesOnly,
Env::Default(), false /* auto_tuned */);
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->LoadDependency(
{{"GenericRateLimiter::Request",
"RateLimiterTest::LimitChangeTest:changeLimitStart"},
{"RateLimiterTest::LimitChangeTest:changeLimitEnd",
"GenericRateLimiter::Refill"}});
Arg arg(target, Env::IO_HIGH, limiter);
// The idea behind is to start a request first, then before it refills,
// update limit to a different value (2X/0.5X). No starvation should
// be guaranteed under any situation
// TODO(lightmark): more test cases are welcome.
env->StartThread(writer, &arg);
int32_t new_limit = (target << 1) >> (iter << 1);
TEST_SYNC_POINT("RateLimiterTest::LimitChangeTest:changeLimitStart");
arg.limiter->SetBytesPerSecond(new_limit);
TEST_SYNC_POINT("RateLimiterTest::LimitChangeTest:changeLimitEnd");
env->WaitForJoin();
fprintf(stderr,
"[COMPLETE] request size %" PRIi32 " KB, new limit %" PRIi32
"KB/sec, refill period %" PRIi64 " ms\n",
target / 1024, new_limit / 1024, refill_period / 1000);
}
}
}
TEST_F(RateLimiterTest, AutoTuneIncreaseWhenFull) {
const std::chrono::seconds kTimePerRefill(1);
const int kRefillsPerTune = 100; // needs to match util/rate_limiter.cc
SpecialEnv special_env(Env::Default());
special_env.no_slowdown_ = true;
special_env.time_elapse_only_sleep_ = true;
auto stats = CreateDBStatistics();
std::unique_ptr<RateLimiter> rate_limiter(new GenericRateLimiter(
1000 /* rate_bytes_per_sec */,
std::chrono::microseconds(kTimePerRefill).count(), 10 /* fairness */,
RateLimiter::Mode::kWritesOnly, &special_env, true /* auto_tuned */));
// Use callback to advance time because we need to advance (1) after Request()
// has determined the bytes are not available; and (2) before Refill()
// computes the next refill time (ensuring refill time in the future allows
// the next request to drain the rate limiter).
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->SetCallBack(
"GenericRateLimiter::Refill", [&](void* /*arg*/) {
special_env.SleepForMicroseconds(static_cast<int>(
std::chrono::microseconds(kTimePerRefill).count()));
});
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->EnableProcessing();
// verify rate limit increases after a sequence of periods where rate limiter
// is always drained
int64_t orig_bytes_per_sec = rate_limiter->GetSingleBurstBytes();
rate_limiter->Request(orig_bytes_per_sec, Env::IO_HIGH, stats.get(),
RateLimiter::OpType::kWrite);
while (std::chrono::microseconds(special_env.NowMicros()) <=
kRefillsPerTune * kTimePerRefill) {
rate_limiter->Request(orig_bytes_per_sec, Env::IO_HIGH, stats.get(),
RateLimiter::OpType::kWrite);
}
int64_t new_bytes_per_sec = rate_limiter->GetSingleBurstBytes();
ASSERT_GT(new_bytes_per_sec, orig_bytes_per_sec);
ROCKSDB_NAMESPACE::SyncPoint::GetInstance()->DisableProcessing();
// decreases after a sequence of periods where rate limiter is not drained
orig_bytes_per_sec = new_bytes_per_sec;
special_env.SleepForMicroseconds(static_cast<int>(
kRefillsPerTune * std::chrono::microseconds(kTimePerRefill).count()));
// make a request so tuner can be triggered
rate_limiter->Request(1 /* bytes */, Env::IO_HIGH, stats.get(),
RateLimiter::OpType::kWrite);
new_bytes_per_sec = rate_limiter->GetSingleBurstBytes();
ASSERT_LT(new_bytes_per_sec, orig_bytes_per_sec);
}
} // namespace ROCKSDB_NAMESPACE
int main(int argc, char** argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}
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