1 files changed, 121 insertions, 0 deletions
diff --git a/src/third_party/wiredtiger/bench/wtperf/wtperf_throttle.c b/src/third_party/wiredtiger/bench/wtperf/wtperf_throttle.c
new file mode 100644
index 00000000000..bba1f629715
--- /dev/null
+++ b/src/third_party/wiredtiger/bench/wtperf/wtperf_throttle.c
@@ -0,0 +1,121 @@
+/*-
+ * 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 =
+		    (uint64_t) (float)(usecs_delta /
+		    throttle_cfg->usecs_increment) *
+		    (float)throttle_cfg->ops_per_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);
+}