/*
* QEMU throttling infrastructure
*
- * Copyright (C) Nodalink, SARL. 2013
+ * Copyright (C) Nodalink, EURL. 2013-2014
+ * Copyright (C) Igalia, S.L. 2015
*
- * Author:
+ * Authors:
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
+#include "qemu/osdep.h"
+#include "qapi/error.h"
#include "qemu/throttle.h"
#include "qemu/timer.h"
#include "block/aio.h"
/* make the bucket leak */
bkt->level = MAX(bkt->level - leak, 0);
+
+ /* if we allow bursts for more than one second we also need to
+ * keep track of bkt->burst_level so the bkt->max goal per second
+ * is attained */
+ if (bkt->burst_length > 1) {
+ leak = (bkt->max * (double) delta_ns) / NANOSECONDS_PER_SECOND;
+ bkt->burst_level = MAX(bkt->burst_level - leak, 0);
+ }
}
/* Calculate the time delta since last leak and make proportionals leaks
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;
}
- extra = bkt->level - bkt->max;
+ 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 (extra <= 0) {
- return 0;
+ /* 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 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) {
+ 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);
+ }
}
- return throttle_do_compute_wait(bkt->avg, extra);
+ return 0;
}
/* This function compute the time that must be waited while this IO
* @next_timestamp: the resulting timer
* @ret: true if a timer must be set
*/
-bool throttle_compute_timer(ThrottleState *ts,
- bool is_write,
- int64_t now,
- int64_t *next_timestamp)
+static bool throttle_compute_timer(ThrottleState *ts,
+ bool is_write,
+ int64_t now,
+ int64_t *next_timestamp)
{
int64_t wait;
}
/* Add timers to event loop */
-void throttle_attach_aio_context(ThrottleState *ts, AioContext *new_context)
+void throttle_timers_attach_aio_context(ThrottleTimers *tt,
+ AioContext *new_context)
+{
+ tt->timers[0] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
+ tt->read_timer_cb, tt->timer_opaque);
+ tt->timers[1] = aio_timer_new(new_context, tt->clock_type, SCALE_NS,
+ tt->write_timer_cb, tt->timer_opaque);
+}
+
+/*
+ * Initialize the ThrottleConfig structure to a valid state
+ * @cfg: the config to initialize
+ */
+void throttle_config_init(ThrottleConfig *cfg)
{
- ts->timers[0] = aio_timer_new(new_context, ts->clock_type, SCALE_NS,
- ts->read_timer_cb, ts->timer_opaque);
- ts->timers[1] = aio_timer_new(new_context, ts->clock_type, SCALE_NS,
- ts->write_timer_cb, ts->timer_opaque);
+ unsigned i;
+ memset(cfg, 0, sizeof(*cfg));
+ for (i = 0; i < BUCKETS_COUNT; i++) {
+ cfg->buckets[i].burst_length = 1;
+ }
}
/* To be called first on the ThrottleState */
-void throttle_init(ThrottleState *ts,
- AioContext *aio_context,
- QEMUClockType clock_type,
- QEMUTimerCB *read_timer_cb,
- QEMUTimerCB *write_timer_cb,
- void *timer_opaque)
+void throttle_init(ThrottleState *ts)
{
memset(ts, 0, sizeof(ThrottleState));
+ throttle_config_init(&ts->cfg);
+}
+
+/* To be called first on the ThrottleTimers */
+void throttle_timers_init(ThrottleTimers *tt,
+ AioContext *aio_context,
+ QEMUClockType clock_type,
+ QEMUTimerCB *read_timer_cb,
+ QEMUTimerCB *write_timer_cb,
+ void *timer_opaque)
+{
+ memset(tt, 0, sizeof(ThrottleTimers));
- ts->clock_type = clock_type;
- ts->read_timer_cb = read_timer_cb;
- ts->write_timer_cb = write_timer_cb;
- ts->timer_opaque = timer_opaque;
- throttle_attach_aio_context(ts, aio_context);
+ tt->clock_type = clock_type;
+ tt->read_timer_cb = read_timer_cb;
+ tt->write_timer_cb = write_timer_cb;
+ tt->timer_opaque = timer_opaque;
+ throttle_timers_attach_aio_context(tt, aio_context);
}
/* destroy a timer */
}
/* Remove timers from event loop */
-void throttle_detach_aio_context(ThrottleState *ts)
+void throttle_timers_detach_aio_context(ThrottleTimers *tt)
{
int i;
for (i = 0; i < 2; i++) {
- throttle_timer_destroy(&ts->timers[i]);
+ throttle_timer_destroy(&tt->timers[i]);
}
}
-/* To be called last on the ThrottleState */
-void throttle_destroy(ThrottleState *ts)
+/* To be called last on the ThrottleTimers */
+void throttle_timers_destroy(ThrottleTimers *tt)
{
- throttle_detach_aio_context(ts);
+ throttle_timers_detach_aio_context(tt);
}
/* is any throttling timer configured */
-bool throttle_have_timer(ThrottleState *ts)
+bool throttle_timers_are_initialized(ThrottleTimers *tt)
{
- if (ts->timers[0]) {
+ if (tt->timers[0]) {
return true;
}
return false;
}
-/* return true if any two throttling parameters conflicts
- *
+/* check if a throttling configuration is valid
* @cfg: the throttling configuration to inspect
- * @ret: true if any conflict detected else false
+ * @ret: true if valid else false
+ * @errp: error object
*/
-bool throttle_conflicting(ThrottleConfig *cfg)
+bool throttle_is_valid(ThrottleConfig *cfg, Error **errp)
{
+ int i;
bool bps_flag, ops_flag;
bool bps_max_flag, ops_max_flag;
(cfg->buckets[THROTTLE_OPS_READ].max ||
cfg->buckets[THROTTLE_OPS_WRITE].max);
- return bps_flag || ops_flag || bps_max_flag || ops_max_flag;
-}
+ if (bps_flag || ops_flag || bps_max_flag || ops_max_flag) {
+ error_setg(errp, "bps/iops/max total values and read/write values"
+ " cannot be used at the same time");
+ return false;
+ }
-/* check if a throttling configuration is valid
- * @cfg: the throttling configuration to inspect
- * @ret: true if valid else false
- */
-bool throttle_is_valid(ThrottleConfig *cfg)
-{
- bool invalid = false;
- int i;
+ if (cfg->op_size &&
+ !cfg->buckets[THROTTLE_OPS_TOTAL].avg &&
+ !cfg->buckets[THROTTLE_OPS_READ].avg &&
+ !cfg->buckets[THROTTLE_OPS_WRITE].avg) {
+ error_setg(errp, "iops size requires an iops value to be set");
+ return false;
+ }
for (i = 0; i < BUCKETS_COUNT; i++) {
- if (cfg->buckets[i].avg < 0) {
- invalid = true;
+ 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;
}
- }
- for (i = 0; i < BUCKETS_COUNT; i++) {
- if (cfg->buckets[i].max < 0) {
- invalid = true;
+ if (!bkt->burst_length) {
+ error_setg(errp, "the burst length cannot be 0");
+ return false;
}
- }
- return !invalid;
-}
+ if (bkt->burst_length > 1 && !bkt->max) {
+ error_setg(errp, "burst length set without burst rate");
+ return false;
+ }
-/* fix bucket parameters */
-static void throttle_fix_bucket(LeakyBucket *bkt)
-{
- double min;
-
- /* zero bucket level */
- bkt->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;
- }
-}
+ if (bkt->max && bkt->burst_length > THROTTLE_VALUE_MAX / bkt->max) {
+ error_setg(errp, "burst length too high for this burst rate");
+ return false;
+ }
-/* take care of canceling a timer */
-static void throttle_cancel_timer(QEMUTimer *timer)
-{
- assert(timer != NULL);
+ if (bkt->max && !bkt->avg) {
+ error_setg(errp, "bps_max/iops_max require corresponding"
+ " bps/iops values");
+ return false;
+ }
+
+ if (bkt->max && bkt->max < bkt->avg) {
+ error_setg(errp, "bps_max/iops_max cannot be lower than bps/iops");
+ return false;
+ }
+ }
- timer_del(timer);
+ return true;
}
/* Used to configure the throttle
*
* @ts: the throttle state we are working on
+ * @clock_type: the group's clock_type
* @cfg: the config to set
*/
-void throttle_config(ThrottleState *ts, ThrottleConfig *cfg)
+void throttle_config(ThrottleState *ts,
+ 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(ts->clock_type);
-
- for (i = 0; i < 2; i++) {
- throttle_cancel_timer(ts->timers[i]);
- }
+ ts->previous_leak = qemu_clock_get_ns(clock_type);
}
/* used to get config
*
* NOTE: this function is not unit tested due to it's usage of timer_mod
*
+ * @tt: the timers structure
* @is_write: the type of operation (read/write)
* @ret: true if the timer has been scheduled else false
*/
-bool throttle_schedule_timer(ThrottleState *ts, bool is_write)
+bool throttle_schedule_timer(ThrottleState *ts,
+ ThrottleTimers *tt,
+ bool is_write)
{
- int64_t now = qemu_clock_get_ns(ts->clock_type);
+ int64_t now = qemu_clock_get_ns(tt->clock_type);
int64_t next_timestamp;
bool must_wait;
}
/* request throttled and timer pending -> do nothing */
- if (timer_pending(ts->timers[is_write])) {
+ if (timer_pending(tt->timers[is_write])) {
return true;
}
/* request throttled and timer not pending -> arm timer */
- timer_mod(ts->timers[is_write], next_timestamp);
+ timer_mod(tt->timers[is_write], next_timestamp);
return true;
}
*/
void throttle_account(ThrottleState *ts, bool is_write, uint64_t size)
{
+ const BucketType bucket_types_size[2][2] = {
+ { THROTTLE_BPS_TOTAL, THROTTLE_BPS_READ },
+ { THROTTLE_BPS_TOTAL, THROTTLE_BPS_WRITE }
+ };
+ const BucketType bucket_types_units[2][2] = {
+ { THROTTLE_OPS_TOTAL, THROTTLE_OPS_READ },
+ { THROTTLE_OPS_TOTAL, THROTTLE_OPS_WRITE }
+ };
double units = 1.0;
+ unsigned i;
/* if cfg.op_size is defined and smaller than size we compute unit count */
if (ts->cfg.op_size && size > ts->cfg.op_size) {
units = (double) size / ts->cfg.op_size;
}
- ts->cfg.buckets[THROTTLE_BPS_TOTAL].level += size;
- ts->cfg.buckets[THROTTLE_OPS_TOTAL].level += units;
+ for (i = 0; i < 2; i++) {
+ LeakyBucket *bkt;
- if (is_write) {
- ts->cfg.buckets[THROTTLE_BPS_WRITE].level += size;
- ts->cfg.buckets[THROTTLE_OPS_WRITE].level += units;
- } else {
- ts->cfg.buckets[THROTTLE_BPS_READ].level += size;
- ts->cfg.buckets[THROTTLE_OPS_READ].level += units;
+ bkt = &ts->cfg.buckets[bucket_types_size[is_write][i]];
+ bkt->level += size;
+ if (bkt->burst_length > 1) {
+ bkt->burst_level += size;
+ }
+
+ bkt = &ts->cfg.buckets[bucket_types_units[is_write][i]];
+ bkt->level += units;
+ if (bkt->burst_length > 1) {
+ bkt->burst_level += units;
+ }
}
}
+/* 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;
+}
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