int64_t throttle_compute_wait(LeakyBucket *bkt)
{
double extra; /* the number of extra units blocking the io */
+ double bucket_size; /* I/O before throttling to bkt->avg */
+ double burst_bucket_size; /* Before throttling to bkt->max */
if (!bkt->avg) {
return 0;
}
- /* If the bucket is full then we have to wait */
- extra = bkt->level - bkt->max * bkt->burst_length;
+ if (!bkt->max) {
+ /* If bkt->max is 0 we still want to allow short bursts of I/O
+ * from the guest, otherwise every other request will be throttled
+ * and performance will suffer considerably. */
+ bucket_size = (double) bkt->avg / 10;
+ burst_bucket_size = 0;
+ } else {
+ /* If we have a burst limit then we have to wait until all I/O
+ * at burst rate has finished before throttling to bkt->avg */
+ bucket_size = bkt->max * bkt->burst_length;
+ burst_bucket_size = (double) bkt->max / 10;
+ }
+
+ /* If the main bucket is full then we have to wait */
+ extra = bkt->level - bucket_size;
if (extra > 0) {
return throttle_do_compute_wait(bkt->avg, extra);
}
- /* If the bucket is not full yet we have to make sure that we
- * fulfill the goal of bkt->max units per second. */
+ /* If the main bucket is not full yet we still have to check the
+ * burst bucket in order to enforce the burst limit */
if (bkt->burst_length > 1) {
- /* We use 1/10 of the max value to smooth the throttling.
- * See throttle_fix_bucket() for more details. */
- extra = bkt->burst_level - bkt->max / 10;
+ assert(bkt->max > 0); /* see throttle_is_valid() */
+ extra = bkt->burst_level - burst_bucket_size;
if (extra > 0) {
return throttle_do_compute_wait(bkt->max, extra);
}
{
assert(*timer != NULL);
- timer_del(*timer);
timer_free(*timer);
*timer = NULL;
}
}
for (i = 0; i < BUCKETS_COUNT; i++) {
- if (cfg->buckets[i].avg < 0 ||
- cfg->buckets[i].max < 0 ||
- cfg->buckets[i].avg > THROTTLE_VALUE_MAX ||
- cfg->buckets[i].max > THROTTLE_VALUE_MAX) {
+ LeakyBucket *bkt = &cfg->buckets[i];
+ if (bkt->avg > THROTTLE_VALUE_MAX || bkt->max > THROTTLE_VALUE_MAX) {
error_setg(errp, "bps/iops/max values must be within [0, %lld]",
THROTTLE_VALUE_MAX);
return false;
}
- if (!cfg->buckets[i].burst_length) {
+ if (!bkt->burst_length) {
error_setg(errp, "the burst length cannot be 0");
return false;
}
- if (cfg->buckets[i].burst_length > 1 && !cfg->buckets[i].max) {
+ if (bkt->burst_length > 1 && !bkt->max) {
error_setg(errp, "burst length set without burst rate");
return false;
}
- if (cfg->buckets[i].max && !cfg->buckets[i].avg) {
+ if (bkt->max && bkt->burst_length > THROTTLE_VALUE_MAX / bkt->max) {
+ error_setg(errp, "burst length too high for this burst rate");
+ return false;
+ }
+
+ if (bkt->max && !bkt->avg) {
error_setg(errp, "bps_max/iops_max require corresponding"
" bps/iops values");
return false;
}
- if (cfg->buckets[i].max && cfg->buckets[i].max < cfg->buckets[i].avg) {
+ if (bkt->max && bkt->max < bkt->avg) {
error_setg(errp, "bps_max/iops_max cannot be lower than bps/iops");
return false;
}
return true;
}
-/* fix bucket parameters */
-static void throttle_fix_bucket(LeakyBucket *bkt)
-{
- double min;
-
- /* zero bucket level */
- bkt->level = bkt->burst_level = 0;
-
- /* The following is done to cope with the Linux CFQ block scheduler
- * which regroup reads and writes by block of 100ms in the guest.
- * When they are two process one making reads and one making writes cfq
- * make a pattern looking like the following:
- * WWWWWWWWWWWRRRRRRRRRRRRRRWWWWWWWWWWWWWwRRRRRRRRRRRRRRRRR
- * Having a max burst value of 100ms of the average will help smooth the
- * throttling
- */
- min = bkt->avg / 10;
- if (bkt->avg && !bkt->max) {
- bkt->max = min;
- }
-}
-
-/* take care of canceling a timer */
-static void throttle_cancel_timer(QEMUTimer *timer)
-{
- assert(timer != NULL);
-
- timer_del(timer);
-}
-
/* Used to configure the throttle
*
* @ts: the throttle state we are working on
- * @tt: the throttle timers we use in this aio context
+ * @clock_type: the group's clock_type
* @cfg: the config to set
*/
void throttle_config(ThrottleState *ts,
- ThrottleTimers *tt,
+ QEMUClockType clock_type,
ThrottleConfig *cfg)
{
int i;
ts->cfg = *cfg;
+ /* Zero bucket level */
for (i = 0; i < BUCKETS_COUNT; i++) {
- throttle_fix_bucket(&ts->cfg.buckets[i]);
+ ts->cfg.buckets[i].level = 0;
+ ts->cfg.buckets[i].burst_level = 0;
}
- ts->previous_leak = qemu_clock_get_ns(tt->clock_type);
-
- for (i = 0; i < 2; i++) {
- throttle_cancel_timer(tt->timers[i]);
- }
+ ts->previous_leak = qemu_clock_get_ns(clock_type);
}
/* used to get config
}
}
+/* return a ThrottleConfig based on the options in a ThrottleLimits
+ *
+ * @arg: the ThrottleLimits object to read from
+ * @cfg: the ThrottleConfig to edit
+ * @errp: error object
+ */
+void throttle_limits_to_config(ThrottleLimits *arg, ThrottleConfig *cfg,
+ Error **errp)
+{
+ if (arg->has_bps_total) {
+ cfg->buckets[THROTTLE_BPS_TOTAL].avg = arg->bps_total;
+ }
+ if (arg->has_bps_read) {
+ cfg->buckets[THROTTLE_BPS_READ].avg = arg->bps_read;
+ }
+ if (arg->has_bps_write) {
+ cfg->buckets[THROTTLE_BPS_WRITE].avg = arg->bps_write;
+ }
+
+ if (arg->has_iops_total) {
+ cfg->buckets[THROTTLE_OPS_TOTAL].avg = arg->iops_total;
+ }
+ if (arg->has_iops_read) {
+ cfg->buckets[THROTTLE_OPS_READ].avg = arg->iops_read;
+ }
+ if (arg->has_iops_write) {
+ cfg->buckets[THROTTLE_OPS_WRITE].avg = arg->iops_write;
+ }
+
+ if (arg->has_bps_total_max) {
+ cfg->buckets[THROTTLE_BPS_TOTAL].max = arg->bps_total_max;
+ }
+ if (arg->has_bps_read_max) {
+ cfg->buckets[THROTTLE_BPS_READ].max = arg->bps_read_max;
+ }
+ if (arg->has_bps_write_max) {
+ cfg->buckets[THROTTLE_BPS_WRITE].max = arg->bps_write_max;
+ }
+ if (arg->has_iops_total_max) {
+ cfg->buckets[THROTTLE_OPS_TOTAL].max = arg->iops_total_max;
+ }
+ if (arg->has_iops_read_max) {
+ cfg->buckets[THROTTLE_OPS_READ].max = arg->iops_read_max;
+ }
+ if (arg->has_iops_write_max) {
+ cfg->buckets[THROTTLE_OPS_WRITE].max = arg->iops_write_max;
+ }
+
+ if (arg->has_bps_total_max_length) {
+ if (arg->bps_total_max_length > UINT_MAX) {
+ error_setg(errp, "bps-total-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_BPS_TOTAL].burst_length = arg->bps_total_max_length;
+ }
+ if (arg->has_bps_read_max_length) {
+ if (arg->bps_read_max_length > UINT_MAX) {
+ error_setg(errp, "bps-read-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_BPS_READ].burst_length = arg->bps_read_max_length;
+ }
+ if (arg->has_bps_write_max_length) {
+ if (arg->bps_write_max_length > UINT_MAX) {
+ error_setg(errp, "bps-write-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_BPS_WRITE].burst_length = arg->bps_write_max_length;
+ }
+ if (arg->has_iops_total_max_length) {
+ if (arg->iops_total_max_length > UINT_MAX) {
+ error_setg(errp, "iops-total-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_OPS_TOTAL].burst_length = arg->iops_total_max_length;
+ }
+ if (arg->has_iops_read_max_length) {
+ if (arg->iops_read_max_length > UINT_MAX) {
+ error_setg(errp, "iops-read-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_OPS_READ].burst_length = arg->iops_read_max_length;
+ }
+ if (arg->has_iops_write_max_length) {
+ if (arg->iops_write_max_length > UINT_MAX) {
+ error_setg(errp, "iops-write-max-length value must be in"
+ " the range [0, %u]", UINT_MAX);
+ return;
+ }
+ cfg->buckets[THROTTLE_OPS_WRITE].burst_length = arg->iops_write_max_length;
+ }
+
+ if (arg->has_iops_size) {
+ cfg->op_size = arg->iops_size;
+ }
+
+ throttle_is_valid(cfg, errp);
+}
+
+/* write the options of a ThrottleConfig to a ThrottleLimits
+ *
+ * @cfg: the ThrottleConfig to read from
+ * @var: the ThrottleLimits to write to
+ */
+void throttle_config_to_limits(ThrottleConfig *cfg, ThrottleLimits *var)
+{
+ var->bps_total = cfg->buckets[THROTTLE_BPS_TOTAL].avg;
+ var->bps_read = cfg->buckets[THROTTLE_BPS_READ].avg;
+ var->bps_write = cfg->buckets[THROTTLE_BPS_WRITE].avg;
+ var->iops_total = cfg->buckets[THROTTLE_OPS_TOTAL].avg;
+ var->iops_read = cfg->buckets[THROTTLE_OPS_READ].avg;
+ var->iops_write = cfg->buckets[THROTTLE_OPS_WRITE].avg;
+ var->bps_total_max = cfg->buckets[THROTTLE_BPS_TOTAL].max;
+ var->bps_read_max = cfg->buckets[THROTTLE_BPS_READ].max;
+ var->bps_write_max = cfg->buckets[THROTTLE_BPS_WRITE].max;
+ var->iops_total_max = cfg->buckets[THROTTLE_OPS_TOTAL].max;
+ var->iops_read_max = cfg->buckets[THROTTLE_OPS_READ].max;
+ var->iops_write_max = cfg->buckets[THROTTLE_OPS_WRITE].max;
+ var->bps_total_max_length = cfg->buckets[THROTTLE_BPS_TOTAL].burst_length;
+ var->bps_read_max_length = cfg->buckets[THROTTLE_BPS_READ].burst_length;
+ var->bps_write_max_length = cfg->buckets[THROTTLE_BPS_WRITE].burst_length;
+ var->iops_total_max_length = cfg->buckets[THROTTLE_OPS_TOTAL].burst_length;
+ var->iops_read_max_length = cfg->buckets[THROTTLE_OPS_READ].burst_length;
+ var->iops_write_max_length = cfg->buckets[THROTTLE_OPS_WRITE].burst_length;
+ var->iops_size = cfg->op_size;
+
+ var->has_bps_total = true;
+ var->has_bps_read = true;
+ var->has_bps_write = true;
+ var->has_iops_total = true;
+ var->has_iops_read = true;
+ var->has_iops_write = true;
+ var->has_bps_total_max = true;
+ var->has_bps_read_max = true;
+ var->has_bps_write_max = true;
+ var->has_iops_total_max = true;
+ var->has_iops_read_max = true;
+ var->has_iops_write_max = true;
+ var->has_bps_read_max_length = true;
+ var->has_bps_total_max_length = true;
+ var->has_bps_write_max_length = true;
+ var->has_iops_total_max_length = true;
+ var->has_iops_read_max_length = true;
+ var->has_iops_write_max_length = true;
+ var->has_iops_size = true;
+}
projects / mirror_qemu.git / blobdiff