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authorBrian Foster <bfoster@redhat.com>2012-10-22 19:19:50 -0400
committerAnand Avati <avati@redhat.com>2012-11-21 13:49:47 -0800
commitd8fbd9ec2a674c5bfa80d975dfb328674053f82f (patch)
tree333ebe74acd50d0b305f21f5b0fcc78cc09f5210 /xlators
parent2e40e0f42807f23d447d7fae67c1e2f834904c53 (diff)
perf/io-threads: least-rate-limit least priority throttling
The 'least-rate-limit' io-threads translator option enables throttling of least priority operations. This is initially intended as a debug/diagnostic tool for users who might experience overloaded servers via background activity (i.e., self-heal). least-rate-limit defines the maximum number of least priority operations the io-threads translator will dequeue in one second. If the specified rate limit is met, the worker threads sleep for the minimal amount of time before the next least priority operation becomes available (or until a new request arrives). The requests/second metric is generic and relative to a variety of factors involved with a background operation (server, storage, etc.). The most recent measured rate ("cached least rate") is added to the io-threads state dump content (kill -USR1) to serve as a reference point to throttle background activity under particular conditions. Change-Id: I80f2282992137d57b1becaa5c6ae3858c066862a BUG: 853680 Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-on: http://review.gluster.org/4119 Tested-by: Gluster Build System <jenkins@build.gluster.com> Reviewed-by: Anand Avati <avati@redhat.com>
Diffstat (limited to 'xlators')
-rw-r--r--xlators/mgmt/glusterd/src/glusterd-volgen.c1
-rw-r--r--xlators/performance/io-threads/src/io-threads.c86
-rw-r--r--xlators/performance/io-threads/src/io-threads.h10
3 files changed, 95 insertions, 2 deletions
diff --git a/xlators/mgmt/glusterd/src/glusterd-volgen.c b/xlators/mgmt/glusterd/src/glusterd-volgen.c
index a8c71e29c4c..6f7b3034cbf 100644
--- a/xlators/mgmt/glusterd/src/glusterd-volgen.c
+++ b/xlators/mgmt/glusterd/src/glusterd-volgen.c
@@ -158,6 +158,7 @@ static struct volopt_map_entry glusterd_volopt_map[] = {
{"performance.low-prio-threads", "performance/io-threads", NULL, NULL, DOC, 0, 1},
{"performance.least-prio-threads", "performance/io-threads", NULL, NULL, DOC, 0, 1},
{"performance.enable-least-priority", "performance/io-threads", NULL, NULL, DOC, 0, 2},
+ {"performance.least-rate-limit", "performance/io-threads", NULL, NULL, DOC, 0, 1},
/* Other perf xlators' options */
{"performance.cache-size", "performance/quick-read", NULL, NULL, NO_DOC, 0, 1},
diff --git a/xlators/performance/io-threads/src/io-threads.c b/xlators/performance/io-threads/src/io-threads.c
index 2a5cec7edc2..dbf1929e897 100644
--- a/xlators/performance/io-threads/src/io-threads.c
+++ b/xlators/performance/io-threads/src/io-threads.c
@@ -30,16 +30,69 @@ int __iot_workers_scale (iot_conf_t *conf);
struct volume_options options[];
call_stub_t *
-__iot_dequeue (iot_conf_t *conf, int *pri)
+__iot_dequeue (iot_conf_t *conf, int *pri, struct timespec *sleep)
{
call_stub_t *stub = NULL;
int i = 0;
+ struct timeval curtv = {0,}, difftv = {0,};
*pri = -1;
+ sleep->tv_sec = 0;
+ sleep->tv_nsec = 0;
for (i = 0; i < IOT_PRI_MAX; i++) {
if (list_empty (&conf->reqs[i]) ||
(conf->ac_iot_count[i] >= conf->ac_iot_limit[i]))
continue;
+
+ if (i == IOT_PRI_LEAST) {
+ pthread_mutex_lock(&conf->throttle.lock);
+ if (!conf->throttle.sample_time.tv_sec) {
+ /* initialize */
+ gettimeofday(&conf->throttle.sample_time, NULL);
+ } else {
+ /*
+ * Maintain a running count of least priority
+ * operations that are handled over a particular
+ * time interval. The count is provided via
+ * state dump and is used as a measure against
+ * least priority op throttling.
+ */
+ gettimeofday(&curtv, NULL);
+ timersub(&curtv, &conf->throttle.sample_time,
+ &difftv);
+ if (difftv.tv_sec >= IOT_LEAST_THROTTLE_DELAY) {
+ conf->throttle.cached_rate =
+ conf->throttle.sample_cnt;
+ conf->throttle.sample_cnt = 0;
+ conf->throttle.sample_time = curtv;
+ }
+
+ /*
+ * If we're over the configured rate limit,
+ * provide an absolute time to the caller that
+ * represents the soonest we're allowed to
+ * return another least priority request.
+ */
+ if (conf->throttle.rate_limit &&
+ conf->throttle.sample_cnt >=
+ conf->throttle.rate_limit) {
+ struct timeval delay;
+ delay.tv_sec = IOT_LEAST_THROTTLE_DELAY;
+ delay.tv_usec = 0;
+
+ timeradd(&conf->throttle.sample_time,
+ &delay, &curtv);
+ TIMEVAL_TO_TIMESPEC(&curtv, sleep);
+
+ pthread_mutex_unlock(
+ &conf->throttle.lock);
+ break;
+ }
+ }
+ conf->throttle.sample_cnt++;
+ pthread_mutex_unlock(&conf->throttle.lock);
+ }
+
stub = list_entry (conf->reqs[i].next, call_stub_t, list);
conf->ac_iot_count[i]++;
*pri = i;
@@ -83,6 +136,7 @@ iot_worker (void *data)
int pri = -1;
char timeout = 0;
char bye = 0;
+ struct timespec sleep = {0,};
conf = data;
this = conf->this;
@@ -123,7 +177,13 @@ iot_worker (void *data)
}
}
- stub = __iot_dequeue (conf, &pri);
+ stub = __iot_dequeue (conf, &pri, &sleep);
+ if (!stub && (sleep.tv_sec || sleep.tv_nsec)) {
+ pthread_cond_timedwait(&conf->cond,
+ &conf->mutex, &sleep);
+ pthread_mutex_unlock(&conf->mutex);
+ continue;
+ }
}
pthread_mutex_unlock (&conf->mutex);
@@ -2485,6 +2545,10 @@ iot_priv_dump (xlator_t *this)
gf_proc_dump_write("least_priority_threads", "%d",
conf->ac_iot_limit[IOT_PRI_LEAST]);
+ gf_proc_dump_write("cached least rate", "%u",
+ conf->throttle.cached_rate);
+ gf_proc_dump_write("least rate limit", "%u", conf->throttle.rate_limit);
+
return 0;
}
@@ -2516,6 +2580,9 @@ reconfigure (xlator_t *this, dict_t *options)
GF_OPTION_RECONF ("enable-least-priority", conf->least_priority,
options, bool, out);
+ GF_OPTION_RECONF("least-rate-limit", conf->throttle.rate_limit, options,
+ int32, out);
+
ret = 0;
out:
return ret;
@@ -2580,6 +2647,14 @@ init (xlator_t *this)
GF_OPTION_INIT ("enable-least-priority", conf->least_priority,
bool, out);
+ GF_OPTION_INIT("least-rate-limit", conf->throttle.rate_limit, int32,
+ out);
+ if ((ret = pthread_mutex_init(&conf->throttle.lock, NULL)) != 0) {
+ gf_log (this->name, GF_LOG_ERROR,
+ "pthread_mutex_init failed (%d)", ret);
+ goto out;
+ }
+
conf->this = this;
for (i = 0; i < IOT_PRI_MAX; i++) {
@@ -2722,6 +2797,13 @@ struct volume_options options[] = {
.max = 0x7fffffff,
.default_value = "120",
},
+ {.key = {"least-rate-limit"},
+ .type = GF_OPTION_TYPE_INT,
+ .min = 0,
+ .default_value = "0",
+ .description = "Max number of least priority operations to handle "
+ "per-second"
+ },
{ .key = {NULL},
},
};
diff --git a/xlators/performance/io-threads/src/io-threads.h b/xlators/performance/io-threads/src/io-threads.h
index a6b640884d0..1a9dee9ae2c 100644
--- a/xlators/performance/io-threads/src/io-threads.h
+++ b/xlators/performance/io-threads/src/io-threads.h
@@ -53,6 +53,14 @@ typedef enum {
IOT_PRI_MAX,
} iot_pri_t;
+#define IOT_LEAST_THROTTLE_DELAY 1 /* sample interval in seconds */
+struct iot_least_throttle {
+ struct timeval sample_time; /* timestamp of current sample */
+ uint32_t sample_cnt; /* sample count for active interval */
+ uint32_t cached_rate; /* the most recently measured rate */
+ int32_t rate_limit; /* user-specified rate limit */
+ pthread_mutex_t lock;
+};
struct iot_conf {
pthread_mutex_t mutex;
@@ -75,6 +83,8 @@ struct iot_conf {
xlator_t *this;
size_t stack_size;
+
+ struct iot_least_throttle throttle;
};
typedef struct iot_conf iot_conf_t;