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#pragma once
#include <util/datetime/base.h>
#include <util/system/mutex.h>
#include <util/system/hp_timer.h>
/* Token bucket.
* Makes flow of *inflow* units per second in average, with up to *capacity* bursts.
* Do not use for STRICT flow control.
*/
/* samples: create and use quoter sending 1000 bytes per second on average,
with up to 60 seconds quota buildup.
TBucketQuoter quoter(1000, 60000, NULL, NULL, NULL);
for (;;) {
T *msg = get_message();
quoter.Sleep();
quoter.Use(msg->GetSize());
send_message(msg);
}
----------------------------
TBucketQuoter quoter(1000, 60000, NULL, NULL, NULL);
for (;;) {
T *msg = get_message();
while (! quoter.IsAvail()) {
// do something else
}
quoter.Use(msg->GetSize());
send_message(msg);
}
*/
struct TInstantTimerMs {
using TTime = TInstant;
static constexpr ui64 Resolution = 1000ull; // milliseconds
static TTime Now() {
return TInstant::Now();
}
static ui64 Duration(TTime from, TTime to) {
return (to - from).MilliSeconds();
}
};
struct THPTimerUs {
using TTime = NHPTimer::STime;
static constexpr ui64 Resolution = 1000000ull; // microseconds
static TTime Now() {
NHPTimer::STime ret;
NHPTimer::GetTime(&ret);
return ret;
}
static ui64 Duration(TTime from, TTime to) {
i64 cycles = to - from;
if (cycles > 0) {
return ui64(double(cycles) * double(Resolution) / NHPTimer::GetClockRate());
} else {
return 0;
}
}
};
template <typename StatCounter, typename Lock = TMutex, typename Timer = TInstantTimerMs>
class TBucketQuoter {
public:
using TTime = typename Timer::TTime;
struct TResult {
i64 Before;
i64 After;
ui64 Seqno;
};
/* fixed quota */
TBucketQuoter(ui64 inflow, ui64 capacity, StatCounter* msgPassed = nullptr,
StatCounter* bucketUnderflows = nullptr, StatCounter* tokensUsed = nullptr,
StatCounter* usecWaited = nullptr, bool fill = false, StatCounter* aggregateInflow = nullptr)
: MsgPassed(msgPassed)
, BucketUnderflows(bucketUnderflows)
, TokensUsed(tokensUsed)
, UsecWaited(usecWaited)
, AggregateInflow(aggregateInflow)
, Bucket(fill ? capacity : 0)
, LastAdd(Timer::Now())
, InflowTokensPerSecond(&FixedInflow)
, BucketTokensCapacity(&FixedCapacity)
, FixedInflow(inflow)
, FixedCapacity(capacity)
{
/* no-op */
}
/* adjustable quotas */
TBucketQuoter(TAtomic* inflow, TAtomic* capacity, StatCounter* msgPassed = nullptr,
StatCounter* bucketUnderflows = nullptr, StatCounter* tokensUsed = nullptr,
StatCounter* usecWaited = nullptr, bool fill = false, StatCounter* aggregateInflow = nullptr)
: MsgPassed(msgPassed)
, BucketUnderflows(bucketUnderflows)
, TokensUsed(tokensUsed)
, UsecWaited(usecWaited)
, AggregateInflow(aggregateInflow)
, Bucket(fill ? AtomicGet(*capacity) : 0)
, LastAdd(Timer::Now())
, InflowTokensPerSecond(inflow)
, BucketTokensCapacity(capacity)
{
/* no-op */
}
bool IsAvail() {
TGuard<Lock> g(BucketMutex);
FillBucket();
if (Bucket < 0) {
if (BucketUnderflows) {
(*BucketUnderflows)++;
}
}
return (Bucket >= 0);
}
bool IsAvail(TResult& res) {
TGuard<Lock> g(BucketMutex);
res.Before = Bucket;
FillBucket();
res.After = Bucket;
res.Seqno = ++Seqno;
if (Bucket < 0) {
if (BucketUnderflows) {
(*BucketUnderflows)++;
}
}
return (Bucket >= 0);
}
ui64 GetAvail() {
TGuard<Lock> g(BucketMutex);
FillBucket();
return Max<i64>(0, Bucket);
}
ui64 GetAvail(TResult& res) {
TGuard<Lock> g(BucketMutex);
res.Before = Bucket;
FillBucket();
res.After = Bucket;
res.Seqno = ++Seqno;
return Max<i64>(0, Bucket);
}
void Use(ui64 tokens, bool sleep = false) {
TGuard<Lock> g(BucketMutex);
UseNoLock(tokens, sleep);
}
void Use(ui64 tokens, TResult& res, bool sleep = false) {
TGuard<Lock> g(BucketMutex);
res.Before = Bucket;
UseNoLock(tokens, sleep);
res.After = Bucket;
res.Seqno = ++Seqno;
}
i64 UseAndFill(ui64 tokens) {
TGuard<Lock> g(BucketMutex);
UseNoLock(tokens);
FillBucket();
return Bucket;
}
void Add(ui64 tokens) {
TGuard<Lock> g(BucketMutex);
AddNoLock(tokens);
}
void Add(ui64 tokens, TResult& res) {
TGuard<Lock> g(BucketMutex);
res.Before = Bucket;
AddNoLock(tokens);
res.After = Bucket;
res.Seqno = ++Seqno;
}
ui32 GetWaitTime() {
TGuard<Lock> g(BucketMutex);
FillBucket();
if (Bucket >= 0) {
return 0;
}
ui32 usec = (-Bucket * 1000000) / (*InflowTokensPerSecond);
return usec;
}
ui32 GetWaitTime(TResult& res) {
TGuard<Lock> g(BucketMutex);
res.Before = Bucket;
FillBucket();
res.After = Bucket;
res.Seqno = ++Seqno;
if (Bucket >= 0) {
return 0;
}
ui32 usec = (-Bucket * 1000000) / (*InflowTokensPerSecond);
return usec;
}
void Sleep() {
while (!IsAvail()) {
ui32 delay = GetWaitTime();
if (delay != 0) {
usleep(delay);
if (UsecWaited) {
(*UsecWaited) += delay;
}
}
}
}
private:
void FillBucket() {
TTime now = Timer::Now();
ui64 elapsed = Timer::Duration(LastAdd, now);
if (*InflowTokensPerSecond * elapsed >= Timer::Resolution) {
ui64 inflow = *InflowTokensPerSecond * elapsed / Timer::Resolution;
if (AggregateInflow) {
*AggregateInflow += inflow;
}
Bucket += inflow;
if (Bucket > *BucketTokensCapacity) {
Bucket = *BucketTokensCapacity;
}
LastAdd = now;
}
}
void UseNoLock(ui64 tokens, bool sleep = false) {
if (sleep)
Sleep();
Bucket -= tokens;
if (TokensUsed) {
(*TokensUsed) += tokens;
}
if (MsgPassed) {
(*MsgPassed)++;
}
}
void AddNoLock(ui64 tokens) {
Bucket += tokens;
if (Bucket > *BucketTokensCapacity) {
Bucket = *BucketTokensCapacity;
}
}
StatCounter* MsgPassed;
StatCounter* BucketUnderflows;
StatCounter* TokensUsed;
StatCounter* UsecWaited;
StatCounter* AggregateInflow;
i64 Bucket;
TTime LastAdd;
Lock BucketMutex;
ui64 Seqno = 0;
TAtomic* InflowTokensPerSecond;
TAtomic* BucketTokensCapacity;
TAtomic FixedInflow;
TAtomic FixedCapacity;
};
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