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rocksdb/util/rate_limiter.cc

400 lines
15 KiB

// 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 "monitoring/statistics.h"
#include "port/port.h"
#include "rocksdb/system_clock.h"
#include "test_util/sync_point.h"
#include "util/aligned_buffer.h"
namespace ROCKSDB_NAMESPACE {
size_t RateLimiter::RequestToken(size_t bytes, size_t alignment,
Env::IOPriority io_priority, Statistics* stats,
RateLimiter::OpType op_type) {
if (io_priority < Env::IO_TOTAL && IsRateLimited(op_type)) {
bytes = std::min(bytes, static_cast<size_t>(GetSingleBurstBytes()));
if (alignment > 0) {
// Here we may actually require more than burst and block
// but we can not write less than one page at a time on direct I/O
// thus we may want not to use ratelimiter
bytes = std::max(alignment, TruncateToPageBoundary(alignment, bytes));
}
Request(bytes, io_priority, stats, op_type);
}
return bytes;
}
// Pending request
struct GenericRateLimiter::Req {
explicit Req(int64_t _bytes, port::Mutex* _mu)
fix rate limiter to avoid starvation Summary: The current implementation of rate limiter has the possibility to introduce resource starvation when change its limit. This diff aims to fix this problem by consuming request bytes partially. Test Plan: ``` ./rate_limiter_test [==========] Running 4 tests from 1 test case. [----------] Global test environment set-up. [----------] 4 tests from RateLimiterTest [ RUN ] RateLimiterTest.OverflowRate [ OK ] RateLimiterTest.OverflowRate (0 ms) [ RUN ] RateLimiterTest.StartStop [ OK ] RateLimiterTest.StartStop (0 ms) [ RUN ] RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.355712 KB/sec, elapsed 2.00 seconds request size [1 - 1023], limit 20 KB/sec, actual rate: 19.136564 KB/sec, elapsed 2.00 seconds request size [1 - 2047], limit 20 KB/sec, actual rate: 20.783976 KB/sec, elapsed 2.10 seconds request size [1 - 2047], limit 40 KB/sec, actual rate: 39.308144 KB/sec, elapsed 2.10 seconds request size [1 - 4095], limit 40 KB/sec, actual rate: 40.318349 KB/sec, elapsed 2.20 seconds request size [1 - 4095], limit 80 KB/sec, actual rate: 79.667396 KB/sec, elapsed 2.20 seconds request size [1 - 8191], limit 80 KB/sec, actual rate: 81.807158 KB/sec, elapsed 2.30 seconds request size [1 - 8191], limit 160 KB/sec, actual rate: 160.659761 KB/sec, elapsed 2.20 seconds request size [1 - 16383], limit 160 KB/sec, actual rate: 160.700990 KB/sec, elapsed 3.00 seconds request size [1 - 16383], limit 320 KB/sec, actual rate: 317.639481 KB/sec, elapsed 2.50 seconds [ OK ] RateLimiterTest.Rate (22618 ms) [ RUN ] RateLimiterTest.LimitChangeTest [COMPLETE] request size 10 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 10 KB, new limit 5KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 10KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 80KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 160KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 320KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 80KB/sec, refill period 1000 ms [ OK ] RateLimiterTest.LimitChangeTest (5002 ms) [----------] 4 tests from RateLimiterTest (27620 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test case ran. (27621 ms total) [ PASSED ] 4 tests. ``` Reviewers: sdong, IslamAbdelRahman, yiwu, andrewkr Reviewed By: andrewkr Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60207
8 years ago
: request_bytes(_bytes), bytes(_bytes), cv(_mu), granted(false) {}
int64_t request_bytes;
int64_t bytes;
port::CondVar cv;
bool granted;
};
GenericRateLimiter::GenericRateLimiter(
int64_t rate_bytes_per_sec, int64_t refill_period_us, int32_t fairness,
RateLimiter::Mode mode, const std::shared_ptr<SystemClock>& clock,
bool auto_tuned)
: RateLimiter(mode),
refill_period_us_(refill_period_us),
rate_bytes_per_sec_(auto_tuned ? rate_bytes_per_sec / 2
: rate_bytes_per_sec),
refill_bytes_per_period_(
CalculateRefillBytesPerPeriod(rate_bytes_per_sec_)),
clock_(clock),
stop_(false),
exit_cv_(&request_mutex_),
requests_to_wait_(0),
available_bytes_(0),
next_refill_us_(NowMicrosMonotonic()),
fairness_(fairness > 100 ? 100 : fairness),
rnd_((uint32_t)time(nullptr)),
leader_(nullptr),
auto_tuned_(auto_tuned),
num_drains_(0),
prev_num_drains_(0),
max_bytes_per_sec_(rate_bytes_per_sec),
tuned_time_(NowMicrosMonotonic()) {
total_requests_[0] = 0;
total_requests_[1] = 0;
total_bytes_through_[0] = 0;
total_bytes_through_[1] = 0;
}
GenericRateLimiter::~GenericRateLimiter() {
MutexLock g(&request_mutex_);
stop_ = true;
requests_to_wait_ = static_cast<int32_t>(queue_[Env::IO_LOW].size() +
queue_[Env::IO_HIGH].size());
for (auto& r : queue_[Env::IO_HIGH]) {
r->cv.Signal();
}
for (auto& r : queue_[Env::IO_LOW]) {
r->cv.Signal();
}
while (requests_to_wait_ > 0) {
exit_cv_.Wait();
}
}
// This API allows user to dynamically change rate limiter's bytes per second.
void GenericRateLimiter::SetBytesPerSecond(int64_t bytes_per_second) {
assert(bytes_per_second > 0);
rate_bytes_per_sec_ = bytes_per_second;
refill_bytes_per_period_.store(
CalculateRefillBytesPerPeriod(bytes_per_second),
std::memory_order_relaxed);
}
void GenericRateLimiter::Request(int64_t bytes, const Env::IOPriority pri,
Statistics* stats) {
assert(bytes <= refill_bytes_per_period_.load(std::memory_order_relaxed));
fix rate limiter to avoid starvation Summary: The current implementation of rate limiter has the possibility to introduce resource starvation when change its limit. This diff aims to fix this problem by consuming request bytes partially. Test Plan: ``` ./rate_limiter_test [==========] Running 4 tests from 1 test case. [----------] Global test environment set-up. [----------] 4 tests from RateLimiterTest [ RUN ] RateLimiterTest.OverflowRate [ OK ] RateLimiterTest.OverflowRate (0 ms) [ RUN ] RateLimiterTest.StartStop [ OK ] RateLimiterTest.StartStop (0 ms) [ RUN ] RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.355712 KB/sec, elapsed 2.00 seconds request size [1 - 1023], limit 20 KB/sec, actual rate: 19.136564 KB/sec, elapsed 2.00 seconds request size [1 - 2047], limit 20 KB/sec, actual rate: 20.783976 KB/sec, elapsed 2.10 seconds request size [1 - 2047], limit 40 KB/sec, actual rate: 39.308144 KB/sec, elapsed 2.10 seconds request size [1 - 4095], limit 40 KB/sec, actual rate: 40.318349 KB/sec, elapsed 2.20 seconds request size [1 - 4095], limit 80 KB/sec, actual rate: 79.667396 KB/sec, elapsed 2.20 seconds request size [1 - 8191], limit 80 KB/sec, actual rate: 81.807158 KB/sec, elapsed 2.30 seconds request size [1 - 8191], limit 160 KB/sec, actual rate: 160.659761 KB/sec, elapsed 2.20 seconds request size [1 - 16383], limit 160 KB/sec, actual rate: 160.700990 KB/sec, elapsed 3.00 seconds request size [1 - 16383], limit 320 KB/sec, actual rate: 317.639481 KB/sec, elapsed 2.50 seconds [ OK ] RateLimiterTest.Rate (22618 ms) [ RUN ] RateLimiterTest.LimitChangeTest [COMPLETE] request size 10 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 10 KB, new limit 5KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 10KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 80KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 160KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 320KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 80KB/sec, refill period 1000 ms [ OK ] RateLimiterTest.LimitChangeTest (5002 ms) [----------] 4 tests from RateLimiterTest (27620 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test case ran. (27621 ms total) [ PASSED ] 4 tests. ``` Reviewers: sdong, IslamAbdelRahman, yiwu, andrewkr Reviewed By: andrewkr Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60207
8 years ago
TEST_SYNC_POINT("GenericRateLimiter::Request");
TEST_SYNC_POINT_CALLBACK("GenericRateLimiter::Request:1",
&rate_bytes_per_sec_);
MutexLock g(&request_mutex_);
if (auto_tuned_) {
static const int kRefillsPerTune = 100;
std::chrono::microseconds now(NowMicrosMonotonic());
if (now - tuned_time_ >=
kRefillsPerTune * std::chrono::microseconds(refill_period_us_)) {
Status s = Tune();
s.PermitUncheckedError(); //**TODO: What to do on error?
}
}
if (stop_) {
// It is now in the clean-up of ~GenericRateLimiter().
// Therefore any new incoming request will exit from here
// and not get satiesfied.
return;
}
++total_requests_[pri];
if (available_bytes_ >= bytes) {
// Refill thread assigns quota and notifies requests waiting on
// the queue under mutex. So if we get here, that means nobody
// is waiting?
available_bytes_ -= bytes;
total_bytes_through_[pri] += bytes;
return;
}
// Request cannot be satisfied at this moment, enqueue
Req r(bytes, &request_mutex_);
queue_[pri].push_back(&r);
do {
bool timedout = false;
// Leader election:
// Leader request's duty:
// (1) Waiting for the next refill time;
// (2) Refilling the bytes and granting requests.
//
// If the following three conditions are all true for a request,
// then the request is selected as a leader:
// (1) The request thread acquired the request_mutex_ and is running;
// (2) There is currently no leader;
// (3) The request sits at the front of a queue.
//
// If not selected as a leader, the request thread will wait
// for one of the following signals to wake up and
// compete for the request_mutex_:
// (1) Signal from the previous leader to exit since its requested bytes
// are fully granted;
// (2) Signal from the previous leader to particpate in next-round
// leader election;
// (3) Signal from rate limiter's destructor as part of the clean-up.
//
// Therefore, a leader request can only be one of the following types:
// (1) a new incoming request placed at the front of a queue;
// (2) a previous leader request whose quota has not been not fully
// granted yet due to its lower priority, hence still at
// the front of a queue;
// (3) a waiting request at the front of a queue, which got
// signaled by the previous leader to participate in leader election.
if (leader_ == nullptr &&
((!queue_[Env::IO_HIGH].empty() &&
&r == queue_[Env::IO_HIGH].front()) ||
(!queue_[Env::IO_LOW].empty() &&
&r == queue_[Env::IO_LOW].front()))) {
leader_ = &r;
int64_t delta = next_refill_us_ - NowMicrosMonotonic();
delta = delta > 0 ? delta : 0;
if (delta == 0) {
timedout = true;
} else {
// The leader request thread waits till next_refill_us_
int64_t wait_until = clock_->NowMicros() + delta;
RecordTick(stats, NUMBER_RATE_LIMITER_DRAINS);
++num_drains_;
timedout = r.cv.TimedWait(wait_until);
}
} else {
r.cv.Wait();
}
if (stop_) {
// It is now in the clean-up of ~GenericRateLimiter().
// Therefore any woken-up request will exit here,
// might or might not has been satiesfied.
--requests_to_wait_;
exit_cv_.Signal();
return;
}
// Assertion: request thread running through this point is one of the
// following in terms of the request type and quota granting situation:
// (1) a leader request that is not fully granted with quota and about
// to carry out its leader's work;
// (2) a non-leader request that got fully granted with quota and is
// running to exit;
// (3) a non-leader request that is not fully granted with quota and
// is running to particpate in next-round leader election.
assert((&r == leader_ && !r.granted) || (&r != leader_ && r.granted) ||
(&r != leader_ && !r.granted));
// Assertion: request thread running through this point is one of the
// following in terms of its position in queue:
// (1) a request got popped off the queue because it is fully granted
// with bytes;
// (2) a request sits at the front of its queue.
assert(r.granted ||
(!queue_[Env::IO_HIGH].empty() &&
&r == queue_[Env::IO_HIGH].front()) ||
(!queue_[Env::IO_LOW].empty() &&
&r == queue_[Env::IO_LOW].front()));
if (leader_ == &r) {
// The leader request thread is now running.
// It might or might not has been TimedWait().
if (timedout) {
// Time for the leader to do refill and grant bytes to requests
RefillBytesAndGrantRequests();
// The leader request retires after refilling and granting bytes
// regardless. This is to simplify the election handling.
leader_ = nullptr;
if (r.granted) {
// The leader request (that was just retired)
// already got fully granted with quota and will soon exit
// Assertion: the fully granted leader request is popped off its queue
assert((queue_[Env::IO_HIGH].empty() ||
&r != queue_[Env::IO_HIGH].front()) &&
(queue_[Env::IO_LOW].empty() ||
&r != queue_[Env::IO_LOW].front()));
// If there is any remaining requests, the leader request (that was
// just retired) makes sure there exists at least one leader candidate
// by signaling a front request of a queue to particpate in
// next-round leader election
if (!queue_[Env::IO_HIGH].empty()) {
queue_[Env::IO_HIGH].front()->cv.Signal();
} else if (!queue_[Env::IO_LOW].empty()) {
queue_[Env::IO_LOW].front()->cv.Signal();
}
// The leader request (that was just retired) exits
break;
} else {
// The leader request (that was just retired) is not fully granted
// with quota. It will particpate in leader election and claim back
// the leader position immediately.
assert(!r.granted);
}
} else {
// Spontaneous wake up, need to continue to wait
assert(!r.granted);
leader_ = nullptr;
}
} else {
// The non-leader request thread is running.
// It is one of the following request types:
// (1) The request got fully granted with quota and signaled to run to
// exit by the previous leader;
// (2) The request is not fully granted with quota and signaled to run to
// particpate in next-round leader election by the previous leader.
// It might or might not become the next-round leader because a new
// request may come in and acquire the request_mutex_ before this
// request thread does after it was signaled. The new request might
// sit at front of a queue and hence become the next-round leader
// instead.
assert(&r != leader_);
}
} while (!r.granted);
}
void GenericRateLimiter::RefillBytesAndGrantRequests() {
TEST_SYNC_POINT("GenericRateLimiter::RefillBytesAndGrantRequests");
next_refill_us_ = NowMicrosMonotonic() + refill_period_us_;
// Carry over the left over quota from the last period
auto refill_bytes_per_period =
refill_bytes_per_period_.load(std::memory_order_relaxed);
if (available_bytes_ < refill_bytes_per_period) {
available_bytes_ += refill_bytes_per_period;
}
int use_low_pri_first = rnd_.OneIn(fairness_) ? 0 : 1;
for (int q = 0; q < 2; ++q) {
auto use_pri = (use_low_pri_first == q) ? Env::IO_LOW : Env::IO_HIGH;
auto* queue = &queue_[use_pri];
while (!queue->empty()) {
auto* next_req = queue->front();
fix rate limiter to avoid starvation Summary: The current implementation of rate limiter has the possibility to introduce resource starvation when change its limit. This diff aims to fix this problem by consuming request bytes partially. Test Plan: ``` ./rate_limiter_test [==========] Running 4 tests from 1 test case. [----------] Global test environment set-up. [----------] 4 tests from RateLimiterTest [ RUN ] RateLimiterTest.OverflowRate [ OK ] RateLimiterTest.OverflowRate (0 ms) [ RUN ] RateLimiterTest.StartStop [ OK ] RateLimiterTest.StartStop (0 ms) [ RUN ] RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.355712 KB/sec, elapsed 2.00 seconds request size [1 - 1023], limit 20 KB/sec, actual rate: 19.136564 KB/sec, elapsed 2.00 seconds request size [1 - 2047], limit 20 KB/sec, actual rate: 20.783976 KB/sec, elapsed 2.10 seconds request size [1 - 2047], limit 40 KB/sec, actual rate: 39.308144 KB/sec, elapsed 2.10 seconds request size [1 - 4095], limit 40 KB/sec, actual rate: 40.318349 KB/sec, elapsed 2.20 seconds request size [1 - 4095], limit 80 KB/sec, actual rate: 79.667396 KB/sec, elapsed 2.20 seconds request size [1 - 8191], limit 80 KB/sec, actual rate: 81.807158 KB/sec, elapsed 2.30 seconds request size [1 - 8191], limit 160 KB/sec, actual rate: 160.659761 KB/sec, elapsed 2.20 seconds request size [1 - 16383], limit 160 KB/sec, actual rate: 160.700990 KB/sec, elapsed 3.00 seconds request size [1 - 16383], limit 320 KB/sec, actual rate: 317.639481 KB/sec, elapsed 2.50 seconds [ OK ] RateLimiterTest.Rate (22618 ms) [ RUN ] RateLimiterTest.LimitChangeTest [COMPLETE] request size 10 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 10 KB, new limit 5KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 10KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 80KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 160KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 320KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 80KB/sec, refill period 1000 ms [ OK ] RateLimiterTest.LimitChangeTest (5002 ms) [----------] 4 tests from RateLimiterTest (27620 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test case ran. (27621 ms total) [ PASSED ] 4 tests. ``` Reviewers: sdong, IslamAbdelRahman, yiwu, andrewkr Reviewed By: andrewkr Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60207
8 years ago
if (available_bytes_ < next_req->request_bytes) {
// Grant partial request_bytes to avoid starvation of requests
// that become asking for more bytes than available_bytes_
// due to dynamically reduced rate limiter's bytes_per_second that
// leads to reduced refill_bytes_per_period hence available_bytes_
fix rate limiter to avoid starvation Summary: The current implementation of rate limiter has the possibility to introduce resource starvation when change its limit. This diff aims to fix this problem by consuming request bytes partially. Test Plan: ``` ./rate_limiter_test [==========] Running 4 tests from 1 test case. [----------] Global test environment set-up. [----------] 4 tests from RateLimiterTest [ RUN ] RateLimiterTest.OverflowRate [ OK ] RateLimiterTest.OverflowRate (0 ms) [ RUN ] RateLimiterTest.StartStop [ OK ] RateLimiterTest.StartStop (0 ms) [ RUN ] RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.355712 KB/sec, elapsed 2.00 seconds request size [1 - 1023], limit 20 KB/sec, actual rate: 19.136564 KB/sec, elapsed 2.00 seconds request size [1 - 2047], limit 20 KB/sec, actual rate: 20.783976 KB/sec, elapsed 2.10 seconds request size [1 - 2047], limit 40 KB/sec, actual rate: 39.308144 KB/sec, elapsed 2.10 seconds request size [1 - 4095], limit 40 KB/sec, actual rate: 40.318349 KB/sec, elapsed 2.20 seconds request size [1 - 4095], limit 80 KB/sec, actual rate: 79.667396 KB/sec, elapsed 2.20 seconds request size [1 - 8191], limit 80 KB/sec, actual rate: 81.807158 KB/sec, elapsed 2.30 seconds request size [1 - 8191], limit 160 KB/sec, actual rate: 160.659761 KB/sec, elapsed 2.20 seconds request size [1 - 16383], limit 160 KB/sec, actual rate: 160.700990 KB/sec, elapsed 3.00 seconds request size [1 - 16383], limit 320 KB/sec, actual rate: 317.639481 KB/sec, elapsed 2.50 seconds [ OK ] RateLimiterTest.Rate (22618 ms) [ RUN ] RateLimiterTest.LimitChangeTest [COMPLETE] request size 10 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 10 KB, new limit 5KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 10KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 80KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 160KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 320KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 80KB/sec, refill period 1000 ms [ OK ] RateLimiterTest.LimitChangeTest (5002 ms) [----------] 4 tests from RateLimiterTest (27620 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test case ran. (27621 ms total) [ PASSED ] 4 tests. ``` Reviewers: sdong, IslamAbdelRahman, yiwu, andrewkr Reviewed By: andrewkr Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60207
8 years ago
next_req->request_bytes -= available_bytes_;
available_bytes_ = 0;
break;
}
fix rate limiter to avoid starvation Summary: The current implementation of rate limiter has the possibility to introduce resource starvation when change its limit. This diff aims to fix this problem by consuming request bytes partially. Test Plan: ``` ./rate_limiter_test [==========] Running 4 tests from 1 test case. [----------] Global test environment set-up. [----------] 4 tests from RateLimiterTest [ RUN ] RateLimiterTest.OverflowRate [ OK ] RateLimiterTest.OverflowRate (0 ms) [ RUN ] RateLimiterTest.StartStop [ OK ] RateLimiterTest.StartStop (0 ms) [ RUN ] RateLimiterTest.Rate request size [1 - 1023], limit 10 KB/sec, actual rate: 10.355712 KB/sec, elapsed 2.00 seconds request size [1 - 1023], limit 20 KB/sec, actual rate: 19.136564 KB/sec, elapsed 2.00 seconds request size [1 - 2047], limit 20 KB/sec, actual rate: 20.783976 KB/sec, elapsed 2.10 seconds request size [1 - 2047], limit 40 KB/sec, actual rate: 39.308144 KB/sec, elapsed 2.10 seconds request size [1 - 4095], limit 40 KB/sec, actual rate: 40.318349 KB/sec, elapsed 2.20 seconds request size [1 - 4095], limit 80 KB/sec, actual rate: 79.667396 KB/sec, elapsed 2.20 seconds request size [1 - 8191], limit 80 KB/sec, actual rate: 81.807158 KB/sec, elapsed 2.30 seconds request size [1 - 8191], limit 160 KB/sec, actual rate: 160.659761 KB/sec, elapsed 2.20 seconds request size [1 - 16383], limit 160 KB/sec, actual rate: 160.700990 KB/sec, elapsed 3.00 seconds request size [1 - 16383], limit 320 KB/sec, actual rate: 317.639481 KB/sec, elapsed 2.50 seconds [ OK ] RateLimiterTest.Rate (22618 ms) [ RUN ] RateLimiterTest.LimitChangeTest [COMPLETE] request size 10 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 10 KB, new limit 5KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 20 KB, new limit 10KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 80KB/sec, refill period 1000 ms [COMPLETE] request size 40 KB, new limit 20KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 160KB/sec, refill period 1000 ms [COMPLETE] request size 80 KB, new limit 40KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 320KB/sec, refill period 1000 ms [COMPLETE] request size 160 KB, new limit 80KB/sec, refill period 1000 ms [ OK ] RateLimiterTest.LimitChangeTest (5002 ms) [----------] 4 tests from RateLimiterTest (27620 ms total) [----------] Global test environment tear-down [==========] 4 tests from 1 test case ran. (27621 ms total) [ PASSED ] 4 tests. ``` Reviewers: sdong, IslamAbdelRahman, yiwu, andrewkr Reviewed By: andrewkr Subscribers: andrewkr, dhruba, leveldb Differential Revision: https://reviews.facebook.net/D60207
8 years ago
available_bytes_ -= next_req->request_bytes;
next_req->request_bytes = 0;
total_bytes_through_[use_pri] += next_req->bytes;
queue->pop_front();
next_req->granted = true;
if (next_req != leader_) {
// Quota granted, signal the thread to exit
next_req->cv.Signal();
}
}
}
}
int64_t GenericRateLimiter::CalculateRefillBytesPerPeriod(
int64_t rate_bytes_per_sec) {
if (port::kMaxInt64 / rate_bytes_per_sec < refill_period_us_) {
// Avoid unexpected result in the overflow case. The result now is still
// inaccurate but is a number that is large enough.
return port::kMaxInt64 / 1000000;
} else {
return std::max(kMinRefillBytesPerPeriod,
rate_bytes_per_sec * refill_period_us_ / 1000000);
}
}
Status GenericRateLimiter::Tune() {
const int kLowWatermarkPct = 50;
const int kHighWatermarkPct = 90;
const int kAdjustFactorPct = 5;
// computed rate limit will be in
// `[max_bytes_per_sec_ / kAllowedRangeFactor, max_bytes_per_sec_]`.
const int kAllowedRangeFactor = 20;
std::chrono::microseconds prev_tuned_time = tuned_time_;
tuned_time_ = std::chrono::microseconds(NowMicrosMonotonic());
int64_t elapsed_intervals = (tuned_time_ - prev_tuned_time +
std::chrono::microseconds(refill_period_us_) -
std::chrono::microseconds(1)) /
std::chrono::microseconds(refill_period_us_);
// We tune every kRefillsPerTune intervals, so the overflow and division-by-
// zero conditions should never happen.
assert(num_drains_ - prev_num_drains_ <= port::kMaxInt64 / 100);
assert(elapsed_intervals > 0);
int64_t drained_pct =
(num_drains_ - prev_num_drains_) * 100 / elapsed_intervals;
int64_t prev_bytes_per_sec = GetBytesPerSecond();
int64_t new_bytes_per_sec;
if (drained_pct == 0) {
new_bytes_per_sec = max_bytes_per_sec_ / kAllowedRangeFactor;
} else if (drained_pct < kLowWatermarkPct) {
// sanitize to prevent overflow
int64_t sanitized_prev_bytes_per_sec =
std::min(prev_bytes_per_sec, port::kMaxInt64 / 100);
new_bytes_per_sec =
std::max(max_bytes_per_sec_ / kAllowedRangeFactor,
sanitized_prev_bytes_per_sec * 100 / (100 + kAdjustFactorPct));
} else if (drained_pct > kHighWatermarkPct) {
// sanitize to prevent overflow
int64_t sanitized_prev_bytes_per_sec = std::min(
prev_bytes_per_sec, port::kMaxInt64 / (100 + kAdjustFactorPct));
new_bytes_per_sec =
std::min(max_bytes_per_sec_,
sanitized_prev_bytes_per_sec * (100 + kAdjustFactorPct) / 100);
} else {
new_bytes_per_sec = prev_bytes_per_sec;
}
if (new_bytes_per_sec != prev_bytes_per_sec) {
SetBytesPerSecond(new_bytes_per_sec);
}
num_drains_ = prev_num_drains_;
return Status::OK();
}
RateLimiter* NewGenericRateLimiter(
int64_t rate_bytes_per_sec, int64_t refill_period_us /* = 100 * 1000 */,
int32_t fairness /* = 10 */,
RateLimiter::Mode mode /* = RateLimiter::Mode::kWritesOnly */,
bool auto_tuned /* = false */) {
assert(rate_bytes_per_sec > 0);
assert(refill_period_us > 0);
assert(fairness > 0);
return new GenericRateLimiter(rate_bytes_per_sec, refill_period_us, fairness,
mode, SystemClock::Default(), auto_tuned);
}
} // namespace ROCKSDB_NAMESPACE