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/*-
* Public Domain 2014-2015 MongoDB, Inc.
* Public Domain 2008-2014 WiredTiger, Inc.
*
* This is free and unencumbered software released into the public domain.
*
* Anyone is free to copy, modify, publish, use, compile, sell, or
* distribute this software, either in source code form or as a compiled
* binary, for any purpose, commercial or non-commercial, and by any
* means.
*
* In jurisdictions that recognize copyright laws, the author or authors
* of this software dedicate any and all copyright interest in the
* software to the public domain. We make this dedication for the benefit
* of the public at large and to the detriment of our heirs and
* successors. We intend this dedication to be an overt act of
* relinquishment in perpetuity of all present and future rights to this
* software under copyright law.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include "wtperf.h"
/*
* Put the initial config together for running a throttled workload.
*/
int
setup_throttle(CONFIG_THREAD *thread)
{
THROTTLE_CONFIG *throttle_cfg;
throttle_cfg = &thread->throttle_cfg;
/*
* Setup how the number of operations to run each interval in order to
* meet our desired max throughput.
* - If we have a very small number of them we can do one op
* on a larger increment. Given there is overhead in throttle logic
* we want to avoid running the throttle check regularly.
* - For most workloads, we aim to do 100 ops per interval and adjust
* the sleep period accordingly.
* - For high throughput workloads, we aim to do many ops in 100us
* increments.
*/
if (thread->workload->throttle < THROTTLE_OPS) {
/* If the interval is very small, we do one operation */
throttle_cfg->usecs_increment =
USEC_PER_SEC / thread->workload->throttle;
throttle_cfg->ops_per_increment = 1;
} else if (thread->workload->throttle < USEC_PER_SEC / THROTTLE_OPS) {
throttle_cfg->usecs_increment =
USEC_PER_SEC / thread->workload->throttle * THROTTLE_OPS;
throttle_cfg->ops_per_increment = THROTTLE_OPS;
} else {
/* If the interval is large, we do more ops per interval */
throttle_cfg->usecs_increment = USEC_PER_SEC / THROTTLE_OPS;
throttle_cfg->ops_per_increment =
thread->workload->throttle / THROTTLE_OPS;
}
/* Give the queue some initial operations to work with */
throttle_cfg->ops_count = throttle_cfg->ops_per_increment;
/* Set the first timestamp of when we incremented */
WT_RET(__wt_epoch(NULL, &throttle_cfg->last_increment));
return (0);
}
/*
* Run the throttle function. We will sleep if needed and then reload the
* counter to perform more operations.
*/
int
worker_throttle(CONFIG_THREAD *thread)
{
THROTTLE_CONFIG *throttle_cfg;
struct timespec now;
uint64_t usecs_delta;
throttle_cfg = &thread->throttle_cfg;
WT_RET(__wt_epoch(NULL, &now));
/*
* If we did enough operations in the current interval, sleep for
* the rest of the interval. Then add more operations to the queue.
*/
usecs_delta = WT_TIMEDIFF_US(now, throttle_cfg->last_increment);
if (usecs_delta < throttle_cfg->usecs_increment) {
(void)usleep(
(useconds_t)(throttle_cfg->usecs_increment - usecs_delta));
throttle_cfg->ops_count =
throttle_cfg->ops_per_increment;
/*
* After sleeping, set the interval to the current time.
*/
WT_RET(__wt_epoch(NULL, &throttle_cfg->last_increment));
} else {
throttle_cfg->ops_count = (usecs_delta *
throttle_cfg->ops_per_increment) /
throttle_cfg->usecs_increment;
throttle_cfg->last_increment = now;
}
/*
* Take the minimum so we don't overfill the queue.
*/
throttle_cfg->ops_count =
WT_MIN(throttle_cfg->ops_count, thread->workload->throttle);
return (0);
}
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