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Diffstat (limited to 'qemu/util/throttle.c')
| -rw-r--r-- | qemu/util/throttle.c | 489 |
1 files changed, 0 insertions, 489 deletions
diff --git a/qemu/util/throttle.c b/qemu/util/throttle.c deleted file mode 100644 index 71246b234..000000000 --- a/qemu/util/throttle.c +++ /dev/null @@ -1,489 +0,0 @@ -/* - * QEMU throttling infrastructure - * - * Copyright (C) Nodalink, EURL. 2013-2014 - * Copyright (C) Igalia, S.L. 2015 - * - * Authors: - * Benoît Canet <benoit.canet@nodalink.com> - * Alberto Garcia <berto@igalia.com> - * - * This program is free software; you can redistribute it and/or - * modify it under the terms of the GNU General Public License as - * published by the Free Software Foundation; either version 2 or - * (at your option) version 3 of the License. - * - * This program is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - * GNU General Public License for more details. - * - * You should have received a copy of the GNU General Public License - * 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" - -/* This function make a bucket leak - * - * @bkt: the bucket to make leak - * @delta_ns: the time delta - */ -void throttle_leak_bucket(LeakyBucket *bkt, int64_t delta_ns) -{ - double leak; - - /* compute how much to leak */ - leak = (bkt->avg * (double) delta_ns) / NANOSECONDS_PER_SECOND; - - /* 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 - * - * @now: the current timestamp in ns - */ -static void throttle_do_leak(ThrottleState *ts, int64_t now) -{ - /* compute the time elapsed since the last leak */ - int64_t delta_ns = now - ts->previous_leak; - int i; - - ts->previous_leak = now; - - if (delta_ns <= 0) { - return; - } - - /* make each bucket leak */ - for (i = 0; i < BUCKETS_COUNT; i++) { - throttle_leak_bucket(&ts->cfg.buckets[i], delta_ns); - } -} - -/* do the real job of computing the time to wait - * - * @limit: the throttling limit - * @extra: the number of operation to delay - * @ret: the time to wait in ns - */ -static int64_t throttle_do_compute_wait(double limit, double extra) -{ - double wait = extra * NANOSECONDS_PER_SECOND; - wait /= limit; - return wait; -} - -/* This function compute the wait time in ns that a leaky bucket should trigger - * - * @bkt: the leaky bucket we operate on - * @ret: the resulting wait time in ns or 0 if the operation can go through - */ -int64_t throttle_compute_wait(LeakyBucket *bkt) -{ - double extra; /* the number of extra units blocking the io */ - - if (!bkt->avg) { - return 0; - } - - /* If the bucket is full then we have to wait */ - extra = bkt->level - bkt->max * bkt->burst_length; - 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 (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; - if (extra > 0) { - return throttle_do_compute_wait(bkt->max, extra); - } - } - - return 0; -} - -/* This function compute the time that must be waited while this IO - * - * @is_write: true if the current IO is a write, false if it's a read - * @ret: time to wait - */ -static int64_t throttle_compute_wait_for(ThrottleState *ts, - bool is_write) -{ - BucketType to_check[2][4] = { {THROTTLE_BPS_TOTAL, - THROTTLE_OPS_TOTAL, - THROTTLE_BPS_READ, - THROTTLE_OPS_READ}, - {THROTTLE_BPS_TOTAL, - THROTTLE_OPS_TOTAL, - THROTTLE_BPS_WRITE, - THROTTLE_OPS_WRITE}, }; - int64_t wait, max_wait = 0; - int i; - - for (i = 0; i < 4; i++) { - BucketType index = to_check[is_write][i]; - wait = throttle_compute_wait(&ts->cfg.buckets[index]); - if (wait > max_wait) { - max_wait = wait; - } - } - - return max_wait; -} - -/* compute the timer for this type of operation - * - * @is_write: the type of operation - * @now: the current clock timestamp - * @next_timestamp: the resulting timer - * @ret: true if a timer must be set - */ -static bool throttle_compute_timer(ThrottleState *ts, - bool is_write, - int64_t now, - int64_t *next_timestamp) -{ - int64_t wait; - - /* leak proportionally to the time elapsed */ - throttle_do_leak(ts, now); - - /* compute the wait time if any */ - wait = throttle_compute_wait_for(ts, is_write); - - /* if the code must wait compute when the next timer should fire */ - if (wait) { - *next_timestamp = now + wait; - return true; - } - - /* else no need to wait at all */ - *next_timestamp = now; - return false; -} - -/* Add timers to event loop */ -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) -{ - 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) -{ - 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)); - - 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 */ -static void throttle_timer_destroy(QEMUTimer **timer) -{ - assert(*timer != NULL); - - timer_del(*timer); - timer_free(*timer); - *timer = NULL; -} - -/* Remove timers from event loop */ -void throttle_timers_detach_aio_context(ThrottleTimers *tt) -{ - int i; - - for (i = 0; i < 2; i++) { - throttle_timer_destroy(&tt->timers[i]); - } -} - -/* To be called last on the ThrottleTimers */ -void throttle_timers_destroy(ThrottleTimers *tt) -{ - throttle_timers_detach_aio_context(tt); -} - -/* is any throttling timer configured */ -bool throttle_timers_are_initialized(ThrottleTimers *tt) -{ - if (tt->timers[0]) { - return true; - } - - return false; -} - -/* Does any throttling must be done - * - * @cfg: the throttling configuration to inspect - * @ret: true if throttling must be done else false - */ -bool throttle_enabled(ThrottleConfig *cfg) -{ - int i; - - for (i = 0; i < BUCKETS_COUNT; i++) { - if (cfg->buckets[i].avg > 0) { - return true; - } - } - - return false; -} - -/* check if a throttling configuration is valid - * @cfg: the throttling configuration to inspect - * @ret: true if valid else false - * @errp: error object - */ -bool throttle_is_valid(ThrottleConfig *cfg, Error **errp) -{ - int i; - bool bps_flag, ops_flag; - bool bps_max_flag, ops_max_flag; - - bps_flag = cfg->buckets[THROTTLE_BPS_TOTAL].avg && - (cfg->buckets[THROTTLE_BPS_READ].avg || - cfg->buckets[THROTTLE_BPS_WRITE].avg); - - ops_flag = cfg->buckets[THROTTLE_OPS_TOTAL].avg && - (cfg->buckets[THROTTLE_OPS_READ].avg || - cfg->buckets[THROTTLE_OPS_WRITE].avg); - - bps_max_flag = cfg->buckets[THROTTLE_BPS_TOTAL].max && - (cfg->buckets[THROTTLE_BPS_READ].max || - cfg->buckets[THROTTLE_BPS_WRITE].max); - - ops_max_flag = cfg->buckets[THROTTLE_OPS_TOTAL].max && - (cfg->buckets[THROTTLE_OPS_READ].max || - cfg->buckets[THROTTLE_OPS_WRITE].max); - - 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; - } - - 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) { - error_setg(errp, "bps/iops/max values must be within [0, %lld]", - THROTTLE_VALUE_MAX); - return false; - } - - if (!cfg->buckets[i].burst_length) { - error_setg(errp, "the burst length cannot be 0"); - return false; - } - - if (cfg->buckets[i].burst_length > 1 && !cfg->buckets[i].max) { - error_setg(errp, "burst length set without burst rate"); - return false; - } - - if (cfg->buckets[i].max && !cfg->buckets[i].avg) { - error_setg(errp, "bps_max/iops_max require corresponding" - " bps/iops values"); - 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 - * @cfg: the config to set - */ -void throttle_config(ThrottleState *ts, - ThrottleTimers *tt, - ThrottleConfig *cfg) -{ - int i; - - ts->cfg = *cfg; - - for (i = 0; i < BUCKETS_COUNT; i++) { - throttle_fix_bucket(&ts->cfg.buckets[i]); - } - - ts->previous_leak = qemu_clock_get_ns(tt->clock_type); - - for (i = 0; i < 2; i++) { - throttle_cancel_timer(tt->timers[i]); - } -} - -/* used to get config - * - * @ts: the throttle state we are working on - * @cfg: the config to write - */ -void throttle_get_config(ThrottleState *ts, ThrottleConfig *cfg) -{ - *cfg = ts->cfg; -} - - -/* Schedule the read or write timer if needed - * - * 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, - ThrottleTimers *tt, - bool is_write) -{ - int64_t now = qemu_clock_get_ns(tt->clock_type); - int64_t next_timestamp; - bool must_wait; - - must_wait = throttle_compute_timer(ts, - is_write, - now, - &next_timestamp); - - /* request not throttled */ - if (!must_wait) { - return false; - } - - /* request throttled and timer pending -> do nothing */ - if (timer_pending(tt->timers[is_write])) { - return true; - } - - /* request throttled and timer not pending -> arm timer */ - timer_mod(tt->timers[is_write], next_timestamp); - return true; -} - -/* do the accounting for this operation - * - * @is_write: the type of operation (read/write) - * @size: the size of the operation - */ -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; - } - - for (i = 0; i < 2; i++) { - LeakyBucket *bkt; - - 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; - } - } -} - |