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Re: [Qemu-devel] [PATCH V3 for-1.6 2/5] block: Modify the throttling cod
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From: |
Benoît Canet |
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Subject: |
Re: [Qemu-devel] [PATCH V3 for-1.6 2/5] block: Modify the throttling code to implement the leaky bucket algorithm. |
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Date: |
Fri, 26 Jul 2013 11:48:45 +0200 |
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User-agent: |
Mutt/1.5.21 (2010-09-15) |
> I think it is easier to understand written like this:
>
> int64_t total_leak = ((bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL] *
> delta) /
> NANOSECONDS_PER_SECOND);
> if (ios[BLOCK_IO_LIMIT_READ] <= total_leak / 2) {
> read_leak = ios[BLOCK_IO_LIMIT_READ];
> write_leak = total_leak - read_leak;
> /* symetric case */
> } else if (ios[BLOCK_IO_LIMIT_WRITE] <= total_leak / 2) {
> write_leak = ios[BLOCK_IO_LIMIT_WRITE];
> read_leak = total_leak - write_leak;
> /* both bucket above leak count use half the total leak for both */
> } else {
> write_leak = total_leak / 2;
> read_leak = (total_leak + 1) / 2;
> }
Thanks,
I will propagate these changes in the new infinite HZ algorithm I am currently
writing.
>
> > + /* else we consider that limits are separated */
> > + } else {
> > + read_leak = (bs->io_limits.iops[BLOCK_IO_LIMIT_READ] * delta) /
> > + NANOSECONDS_PER_SECOND;
> > + write_leak = (bs->io_limits.iops[BLOCK_IO_LIMIT_WRITE] * delta) /
> > + NANOSECONDS_PER_SECOND;
> > + }
> > +
> > + /* make the buckets leak */
> > + ios[BLOCK_IO_LIMIT_READ] = MAX(ios[BLOCK_IO_LIMIT_READ] - read_leak,
> > 0);
> > + ios[BLOCK_IO_LIMIT_WRITE] = MAX(ios[BLOCK_IO_LIMIT_WRITE] -
> > write_leak, 0);
> > +}
> > +
> > +static void bdrv_leak_if_needed(BlockDriverState *bs)
> > +{
> > + int64_t now;
> > + int64_t delta;
> > +
> > + if (!bs->must_leak) {
> > + return;
> > + }
> > +
> > + bs->must_leak = false;
> > +
> > + now = qemu_get_clock_ns(rt_clock);
> > + delta = now - bs->previous_leak;
> > + bs->previous_leak = now;
> > +
> > + bdrv_make_bps_buckets_leak(bs, delta);
> > + bdrv_make_iops_buckets_leak(bs, delta);
> > +}
> > +
> > +static void bdrv_block_timer_disable(BlockDriverState *bs)
> > +{
> > + if (!bs->block_timer) {
> > + return;
> > }
> >
> > - bs->slice_start = 0;
> > - bs->slice_end = 0;
> > + qemu_del_timer(bs->block_timer);
> > + qemu_free_timer(bs->block_timer);
> > + bs->block_timer = NULL;
> > +}
> > +
> > +static bool bdrv_throttling_is_iddle(BlockDriverState *bs)
>
> I don't quite understad the wording here, is iddle equivalent to idle?
>
> > +{
> > + int64_t delta = qemu_get_clock_ns(rt_clock) - bs->previous_leak;
> > +
> > + if (delta < BLOCK_IO_THROTTLE_PERIOD * 2) {
> > + return false;
> > + }
> > +
> > + /* iddle */
> > + return true;
> > }
> >
> > +/* This callback is the timer in charge of making the leaky buckets leak */
> > static void bdrv_block_timer(void *opaque)
>
> Will be more readable for me if you could rename it to
> bdrv_clock_timer_cb.
>
> > {
> > BlockDriverState *bs = opaque;
> >
> > + /* disable throttling time on iddle for economy purpose */
> > + if (bdrv_throttling_is_iddle(bs)) {
> > + bdrv_block_timer_disable(bs);
> > + return;
> > + }
> > +
> > + /* rearm the timer */
> > + qemu_mod_timer(bs->block_timer,
> > + qemu_get_clock_ns(vm_clock) +
> > + BLOCK_IO_THROTTLE_PERIOD);
> > +
> > + bs->must_leak = true;
> > qemu_co_enter_next(&bs->throttled_reqs);
> > }
> >
> > +static void bdrv_block_timer_enable(BlockDriverState *bs)
> > +{
> > + if (bs->block_timer) {
> > + return;
> > + }
> > +
> > + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
> > + bs->previous_leak = qemu_get_clock_ns(rt_clock);
> > + qemu_mod_timer(bs->block_timer,
> > + qemu_get_clock_ns(vm_clock) +
> > + BLOCK_IO_THROTTLE_PERIOD);
> > +}
> > +
> > void bdrv_io_limits_enable(BlockDriverState *bs)
> > {
> > qemu_co_queue_init(&bs->throttled_reqs);
> > - bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs);
> > bs->io_limits_enabled = true;
> > }
> >
> > @@ -165,15 +302,118 @@ bool bdrv_io_limits_enabled(BlockDriverState *bs)
> > || io_limits->iops[BLOCK_IO_LIMIT_TOTAL];
> > }
> >
> > +/* This function check if the correct bandwith threshold has been exceeded
>
> What does the "correct bandwidth threshold" mean?
>
> And s/bandwith/bandwidth/, series wide.
>
> > + *
> > + * @is_write: true if the current IO is a write, false if it's a read
> > + * @ret: true if threshold has been exceeded else false
> > + */
> > +static bool bdrv_is_bps_threshold_exceeded(BlockDriverState *bs, bool
> > is_write)
> > +{
> > + /* limit is on total read + write bps : do the sum and compare with
> > total
> > + * threshold
> > + */
> > + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) {
> > + int64_t bytes = bs->leaky_buckets.bytes[BLOCK_IO_LIMIT_READ] +
> > + bs->leaky_buckets.bytes[BLOCK_IO_LIMIT_WRITE];
> > + return bs->io_limits.bps_threshold[BLOCK_IO_LIMIT_TOTAL] < bytes;
> > + }
> > +
> > + /* check wether the threshold corresponding to the current io type
> > (read,
> > + * write) has been exceeded
> > + */
> > + if (bs->io_limits.bps[is_write]) {
>
> It looks dangerous to use is_write as index of the array.
>
> > + return bs->io_limits.bps_threshold[is_write] <
> > + bs->leaky_buckets.bytes[is_write];
> > + }
> > +
> > + /* no limit */
> > + return false;
> > +}
> > +
> > +/* This function check if the correct iops threshold has been exceeded
> > + *
> > + * @is_write: true if the current IO is a write, false if it's a read
> > + * @ret: true if threshold has been exceeded else false
> > + */
> > +static bool bdrv_is_iops_threshold_exceeded(BlockDriverState *bs, bool
> > is_write)
> > +{
> > + /* limit is on total read + write iops : do the sum and compare with
> > total
> > + * threshold
> > + */
> > + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
> > + double ios = bs->leaky_buckets.ios[BLOCK_IO_LIMIT_READ] +
> > + bs->leaky_buckets.ios[BLOCK_IO_LIMIT_WRITE];
> > + return bs->io_limits.iops_threshold[BLOCK_IO_LIMIT_TOTAL] < ios;
> > + }
> > +
> > + /* check wether the threshold corresponding to the current io type
> > (read,
> > + * write) has been exceeded
> > + */
> > + if (bs->io_limits.iops[is_write]) {
> > + return bs->io_limits.iops_threshold[is_write] <
> > + bs->leaky_buckets.ios[is_write];
> > + }
> > +
> > + /* no limit */
> > + return false;
> > +}
> > +
> > +/* This function check if any bandwith or iops threshold has been exceeded
> > + *
> > + * @nb_sectors: the number of sectors of the current IO
> > + * @is_write: true if the current IO is a write, false if it's a read
> > + * @ret: true if any threshold has been exceeded else false
> > + */
> > +static bool bdrv_is_any_threshold_exceeded(BlockDriverState *bs, int
> > nb_sectors,
> > + bool is_write)
> > +{
> > + bool bps_ret, iops_ret;
> > +
> > + /* check if any bandwith or per IO threshold has been exceeded */
> > + bps_ret = bdrv_is_bps_threshold_exceeded(bs, is_write);
> > + iops_ret = bdrv_is_iops_threshold_exceeded(bs, is_write);
> > +
> > + /* if so the IO will be blocked so do not account it and return true
> > + * also return false if a bdrv_drain_all is in progress
> > + */
> > + if (!draining && (bps_ret || iops_ret)) {
> > + return true;
> > + }
> > +
> > + /* NOTE: the counter can go above the threshold when authorizing an IO.
> > + * At next call the code will punish the guest by blocking the
> > + * next IO until the counter has been decremented below the
> > threshold.
> > + * This way if a guest issue a jumbo IO bigger than the
> > threshold it
> > + * will have a chance no be authorized and will not result in a
> > guest
> > + * IO deadlock.
> > + */
> > +
> > + /* the IO is authorized so do the accounting and return false */
> > + bs->leaky_buckets.bytes[is_write] += (int64_t)nb_sectors *
> > + BDRV_SECTOR_SIZE;
> > + bs->leaky_buckets.ios[is_write]++;
> > +
> > + return false;
> > +}
> > +
> > static void bdrv_io_limits_intercept(BlockDriverState *bs,
> > bool is_write, int nb_sectors)
> > {
> > - int64_t wait_time = -1;
> > + /* enable block timer if needed when intercepting I/Os */
> > + if (!bs->block_timer) {
>
> Already checking for bs->block_timer in bdrv_block_timer_enable().
>
> > + bdrv_block_timer_enable(bs);
> > + }
> >
> > + bdrv_leak_if_needed(bs);
> > + /* if some IOs are already queued because the bucket is full put the
> > current
> > + * IO at the end of the queue (FIFO)
> > + */
> > if (!qemu_co_queue_empty(&bs->throttled_reqs)) {
> > qemu_co_queue_wait(&bs->throttled_reqs);
> > }
> >
> > + bdrv_leak_if_needed(bs);
> > +
> > /* In fact, we hope to keep each request's timing, in FIFO mode. The
> > next
> > * throttled requests will not be dequeued until the current request is
> > * allowed to be serviced. So if the current request still exceeds the
> > @@ -181,13 +421,19 @@ static void bdrv_io_limits_intercept(BlockDriverState
> > *bs,
> > * be still in throttled_reqs queue.
> > */
> >
> > - while (bdrv_exceed_io_limits(bs, nb_sectors, is_write, &wait_time)) {
> > - qemu_mod_timer(bs->block_timer,
> > - wait_time + qemu_get_clock_ns(vm_clock));
> > + /* if a threshold is exceeded the leaky bucket is full so the code put
> > the
> > + * IO in the throttle_reqs queue until the bucket has leaked enough to
> > be
> > + * not full
> > + */
> > + while (bdrv_is_any_threshold_exceeded(bs, nb_sectors, is_write)) {
> > + bdrv_leak_if_needed(bs);
> > qemu_co_queue_wait_insert_head(&bs->throttled_reqs);
> > + bdrv_leak_if_needed(bs);
> > }
> >
> > + bdrv_leak_if_needed(bs);
> > qemu_co_queue_next(&bs->throttled_reqs);
> > + bdrv_leak_if_needed(bs);
> > }
> >
> > /* check if the path starts with "<protocol>:" */
> > @@ -1439,6 +1685,9 @@ void bdrv_drain_all(void)
> > BlockDriverState *bs;
> > bool busy;
> >
> > + /* tell the throttling code we are draining */
> > + draining = true;
> > +
> > do {
> > busy = qemu_aio_wait();
> >
> > @@ -1457,6 +1706,8 @@ void bdrv_drain_all(void)
> > assert(QLIST_EMPTY(&bs->tracked_requests));
> > assert(qemu_co_queue_empty(&bs->throttled_reqs));
> > }
> > +
> > + draining = false;
> > }
> >
> > /* make a BlockDriverState anonymous by removing from bdrv_state list.
> > @@ -1492,9 +1743,7 @@ static void bdrv_move_feature_fields(BlockDriverState
> > *bs_dest,
> > bs_dest->enable_write_cache = bs_src->enable_write_cache;
> >
> > /* i/o timing parameters */
> > - bs_dest->slice_start = bs_src->slice_start;
> > - bs_dest->slice_end = bs_src->slice_end;
> > - bs_dest->slice_submitted = bs_src->slice_submitted;
> > + bs_dest->leaky_buckets = bs_src->leaky_buckets;
> > bs_dest->io_limits = bs_src->io_limits;
> > bs_dest->throttled_reqs = bs_src->throttled_reqs;
> > bs_dest->block_timer = bs_src->block_timer;
> > @@ -3551,169 +3800,6 @@ void bdrv_aio_cancel(BlockDriverAIOCB *acb)
> > acb->aiocb_info->cancel(acb);
> > }
> >
> > -/* block I/O throttling */
> > -static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors,
> > - bool is_write, double elapsed_time, uint64_t *wait)
> > -{
> > - uint64_t bps_limit = 0;
> > - uint64_t extension;
> > - double bytes_limit, bytes_base, bytes_res;
> > - double slice_time, wait_time;
> > -
> > - if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) {
> > - bps_limit = bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL];
> > - } else if (bs->io_limits.bps[is_write]) {
> > - bps_limit = bs->io_limits.bps[is_write];
> > - } else {
> > - if (wait) {
> > - *wait = 0;
> > - }
> > -
> > - return false;
> > - }
> > -
> > - slice_time = bs->slice_end - bs->slice_start;
> > - slice_time /= (NANOSECONDS_PER_SECOND);
> > - bytes_limit = bps_limit * slice_time;
> > - bytes_base = bs->slice_submitted.bytes[is_write];
> > - if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) {
> > - bytes_base += bs->slice_submitted.bytes[!is_write];
> > - }
> > -
> > - /* bytes_base: the bytes of data which have been read/written; and
> > - * it is obtained from the history statistic info.
> > - * bytes_res: the remaining bytes of data which need to be
> > read/written.
> > - * (bytes_base + bytes_res) / bps_limit: used to calcuate
> > - * the total time for completing reading/writting all data.
> > - */
> > - bytes_res = (unsigned) nb_sectors * BDRV_SECTOR_SIZE;
> > -
> > - if (bytes_base + bytes_res <= bytes_limit) {
> > - if (wait) {
> > - *wait = 0;
> > - }
> > -
> > - return false;
> > - }
> > -
> > - /* Calc approx time to dispatch */
> > - wait_time = (bytes_base + bytes_res) / bps_limit - elapsed_time;
> > -
> > - /* When the I/O rate at runtime exceeds the limits,
> > - * bs->slice_end need to be extended in order that the current
> > statistic
> > - * info can be kept until the timer fire, so it is increased and tuned
> > - * based on the result of experiment.
> > - */
> > - extension = wait_time * NANOSECONDS_PER_SECOND;
> > - extension = DIV_ROUND_UP(extension, BLOCK_IO_SLICE_TIME) *
> > - BLOCK_IO_SLICE_TIME;
> > - bs->slice_end += extension;
> > - if (wait) {
> > - *wait = wait_time * NANOSECONDS_PER_SECOND;
> > - }
> > -
> > - return true;
> > -}
> > -
> > -static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write,
> > - double elapsed_time, uint64_t *wait)
> > -{
> > - uint64_t iops_limit = 0;
> > - double ios_limit, ios_base;
> > - double slice_time, wait_time;
> > -
> > - if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
> > - iops_limit = bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL];
> > - } else if (bs->io_limits.iops[is_write]) {
> > - iops_limit = bs->io_limits.iops[is_write];
> > - } else {
> > - if (wait) {
> > - *wait = 0;
> > - }
> > -
> > - return false;
> > - }
> > -
> > - slice_time = bs->slice_end - bs->slice_start;
> > - slice_time /= (NANOSECONDS_PER_SECOND);
> > - ios_limit = iops_limit * slice_time;
> > - ios_base = bs->slice_submitted.ios[is_write];
> > - if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) {
> > - ios_base += bs->slice_submitted.ios[!is_write];
> > - }
> > -
> > - if (ios_base + 1 <= ios_limit) {
> > - if (wait) {
> > - *wait = 0;
> > - }
> > -
> > - return false;
> > - }
> > -
> > - /* Calc approx time to dispatch, in seconds */
> > - wait_time = (ios_base + 1) / iops_limit;
> > - if (wait_time > elapsed_time) {
> > - wait_time = wait_time - elapsed_time;
> > - } else {
> > - wait_time = 0;
> > - }
> > -
> > - /* Exceeded current slice, extend it by another slice time */
> > - bs->slice_end += BLOCK_IO_SLICE_TIME;
> > - if (wait) {
> > - *wait = wait_time * NANOSECONDS_PER_SECOND;
> > - }
> > -
> > - return true;
> > -}
> > -
> > -static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors,
> > - bool is_write, int64_t *wait)
> > -{
> > - int64_t now, max_wait;
> > - uint64_t bps_wait = 0, iops_wait = 0;
> > - double elapsed_time;
> > - int bps_ret, iops_ret;
> > -
> > - now = qemu_get_clock_ns(vm_clock);
> > - if (now > bs->slice_end) {
> > - bs->slice_start = now;
> > - bs->slice_end = now + BLOCK_IO_SLICE_TIME;
> > - memset(&bs->slice_submitted, 0, sizeof(bs->slice_submitted));
> > - }
> > -
> > - elapsed_time = now - bs->slice_start;
> > - elapsed_time /= (NANOSECONDS_PER_SECOND);
> > -
> > - bps_ret = bdrv_exceed_bps_limits(bs, nb_sectors,
> > - is_write, elapsed_time, &bps_wait);
> > - iops_ret = bdrv_exceed_iops_limits(bs, is_write,
> > - elapsed_time, &iops_wait);
> > - if (bps_ret || iops_ret) {
> > - max_wait = bps_wait > iops_wait ? bps_wait : iops_wait;
> > - if (wait) {
> > - *wait = max_wait;
> > - }
> > -
> > - now = qemu_get_clock_ns(vm_clock);
> > - if (bs->slice_end < now + max_wait) {
> > - bs->slice_end = now + max_wait;
> > - }
> > -
> > - return true;
> > - }
> > -
> > - if (wait) {
> > - *wait = 0;
> > - }
> > -
> > - bs->slice_submitted.bytes[is_write] += (int64_t)nb_sectors *
> > - BDRV_SECTOR_SIZE;
> > - bs->slice_submitted.ios[is_write]++;
> > -
> > - return false;
> > -}
> > -
> > /**************************************************************/
> > /* async block device emulation */
> >
> > diff --git a/blockdev.c b/blockdev.c
> > index c5abd65..491e4d0 100644
> > --- a/blockdev.c
> > +++ b/blockdev.c
> > @@ -280,10 +280,25 @@ static int parse_block_error_action(const char *buf,
> > bool is_read)
> > }
> > }
> >
> > +static bool check_io_limit(int64_t limit)
> > +{
> > + if (!limit) {
> > + return false;
> > + }
> > +
> > + if (limit < (THROTTLE_HZ * 2)) {
> > + return true;
> > + }
> > +
> > + return false;
> > +}
> > +
> > static bool do_check_io_limits(BlockIOLimit *io_limits, Error **errp)
> > {
> > bool bps_flag;
> > bool iops_flag;
> > + bool bps_threshold_flag;
> > + bool iops_threshold_flag;
> >
> > assert(io_limits);
> >
> > @@ -299,13 +314,30 @@ static bool do_check_io_limits(BlockIOLimit
> > *io_limits, Error **errp)
> > return false;
> > }
> >
> > - if (io_limits->bps[BLOCK_IO_LIMIT_TOTAL] < 0 ||
> > - io_limits->bps[BLOCK_IO_LIMIT_WRITE] < 0 ||
> > - io_limits->bps[BLOCK_IO_LIMIT_READ] < 0 ||
> > - io_limits->iops[BLOCK_IO_LIMIT_TOTAL] < 0 ||
> > - io_limits->iops[BLOCK_IO_LIMIT_WRITE] < 0 ||
> > - io_limits->iops[BLOCK_IO_LIMIT_READ] < 0) {
> > - error_setg(errp, "bps and iops values must be 0 or greater");
> > + bps_threshold_flag =
> > + (io_limits->bps_threshold[BLOCK_IO_LIMIT_TOTAL] != 0)
> > + && ((io_limits->bps_threshold[BLOCK_IO_LIMIT_READ] != 0)
> > + || (io_limits->bps_threshold[BLOCK_IO_LIMIT_WRITE] != 0));
> > + iops_threshold_flag =
> > + (io_limits->iops_threshold[BLOCK_IO_LIMIT_TOTAL] != 0)
> > + && ((io_limits->iops_threshold[BLOCK_IO_LIMIT_READ] != 0)
> > + || (io_limits->iops_threshold[BLOCK_IO_LIMIT_WRITE] != 0));
> > + if (bps_threshold_flag || iops_threshold_flag) {
> > + error_setg(errp, "bps_threshold(iops_threshold) and "
> > + "bps_rd_threshold/bps_wr_threshold"
> > + "(iops_rd_threshold/iops_wr_threshold) "
> > + "cannot be used at the same time");
> > + return false;
> > + }
> > +
> > + if (check_io_limit(io_limits->bps[BLOCK_IO_LIMIT_TOTAL]) ||
> > + check_io_limit(io_limits->bps[BLOCK_IO_LIMIT_WRITE]) ||
> > + check_io_limit(io_limits->bps[BLOCK_IO_LIMIT_READ]) ||
> > + check_io_limit(io_limits->iops[BLOCK_IO_LIMIT_TOTAL]) ||
> > + check_io_limit(io_limits->iops[BLOCK_IO_LIMIT_WRITE]) ||
> > + check_io_limit(io_limits->iops[BLOCK_IO_LIMIT_READ])) {
> > + error_setg(errp, "bps and iops values must be %i or greater",
> > + THROTTLE_HZ * 2);
> > return false;
> > }
> >
> > @@ -497,6 +529,18 @@ DriveInfo *drive_init(QemuOpts *all_opts,
> > BlockInterfaceType block_default_type)
> > qemu_opt_get_number(opts, "iops_rd", 0);
> > io_limits.iops[BLOCK_IO_LIMIT_WRITE] =
> > qemu_opt_get_number(opts, "iops_wr", 0);
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_TOTAL] =
> > + io_limits.bps[BLOCK_IO_LIMIT_TOTAL] /
> > THROTTLE_HZ;
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_READ] =
> > + io_limits.bps[BLOCK_IO_LIMIT_READ] /
> > THROTTLE_HZ;
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_WRITE] =
> > + io_limits.bps[BLOCK_IO_LIMIT_WRITE] /
> > THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_TOTAL] =
> > + io_limits.iops[BLOCK_IO_LIMIT_TOTAL] /
> > THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_READ] =
> > + io_limits.iops[BLOCK_IO_LIMIT_READ] /
> > THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_WRITE] =
> > + io_limits.iops[BLOCK_IO_LIMIT_WRITE] /
> > THROTTLE_HZ;
> >
> > if (!do_check_io_limits(&io_limits, &error)) {
> > error_report("%s", error_get_pretty(error));
> > @@ -1198,6 +1242,12 @@ void qmp_block_set_io_throttle(const char *device,
> > int64_t bps, int64_t bps_rd,
> > io_limits.iops[BLOCK_IO_LIMIT_TOTAL]= iops;
> > io_limits.iops[BLOCK_IO_LIMIT_READ] = iops_rd;
> > io_limits.iops[BLOCK_IO_LIMIT_WRITE]= iops_wr;
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_TOTAL] = bps / THROTTLE_HZ;
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_READ] = bps_rd / THROTTLE_HZ;
> > + io_limits.bps_threshold[BLOCK_IO_LIMIT_WRITE] = bps_wr / THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_TOTAL] = iops / THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_READ] = iops_rd / THROTTLE_HZ;
> > + io_limits.iops_threshold[BLOCK_IO_LIMIT_WRITE] = iops_wr / THROTTLE_HZ;
> >
> > if (!do_check_io_limits(&io_limits, errp)) {
> > return;
> > @@ -1209,11 +1259,10 @@ void qmp_block_set_io_throttle(const char *device,
> > int64_t bps, int64_t bps_rd,
> > bdrv_io_limits_enable(bs);
> > } else if (bs->io_limits_enabled && !bdrv_io_limits_enabled(bs)) {
> > bdrv_io_limits_disable(bs);
> > - } else {
> > - if (bs->block_timer) {
> > - qemu_mod_timer(bs->block_timer, qemu_get_clock_ns(vm_clock));
> > - }
> > }
> > +
> > + /* reset leaky bucket to get the system in a known state */
> > + memset(&bs->leaky_buckets, 0, sizeof(bs->leaky_buckets));
> > }
> >
> > int do_drive_del(Monitor *mon, const QDict *qdict, QObject **ret_data)
> > diff --git a/include/block/block_int.h b/include/block/block_int.h
> > index c6ac871..e32ad1f 100644
> > --- a/include/block/block_int.h
> > +++ b/include/block/block_int.h
> > @@ -43,8 +43,9 @@
> > #define BLOCK_IO_LIMIT_WRITE 1
> > #define BLOCK_IO_LIMIT_TOTAL 2
> >
> > -#define BLOCK_IO_SLICE_TIME 100000000
> > #define NANOSECONDS_PER_SECOND 1000000000.0
> > +#define THROTTLE_HZ 1
> > +#define BLOCK_IO_THROTTLE_PERIOD (NANOSECONDS_PER_SECOND / THROTTLE_HZ)
> >
> > #define BLOCK_OPT_SIZE "size"
> > #define BLOCK_OPT_ENCRYPT "encryption"
> > @@ -73,11 +74,13 @@ typedef struct BdrvTrackedRequest {
> > typedef struct BlockIOLimit {
> > int64_t bps[3];
> > int64_t iops[3];
> > + int64_t bps_threshold[3];
> > + int64_t iops_threshold[3];
> > } BlockIOLimit;
> >
> > typedef struct BlockIOBaseValue {
> > - uint64_t bytes[2];
> > - uint64_t ios[2];
> > + int64_t bytes[2];
> > + double ios[2];
> > } BlockIOBaseValue;
> >
> > struct BlockDriver {
> > @@ -264,10 +267,10 @@ struct BlockDriverState {
> > unsigned int copy_on_read_in_flight;
> >
> > /* the time for latest disk I/O */
> > - int64_t slice_start;
> > - int64_t slice_end;
> > BlockIOLimit io_limits;
> > - BlockIOBaseValue slice_submitted;
> > + BlockIOBaseValue leaky_buckets;
> > + int64_t previous_leak;
> > + bool must_leak;
> > CoQueue throttled_reqs;
> > QEMUTimer *block_timer;
> > bool io_limits_enabled;
> > --
> > 1.7.10.4
> >
> >
>
> --
> Fam
>
- [Qemu-devel] [PATCH V3 for-1.6 0/5] Leaky bucket throttling and features, Benoît Canet, 2013/07/23
- [Qemu-devel] [PATCH V3 for-1.6 1/5] block: Repair the throttling code., Benoît Canet, 2013/07/23
- [Qemu-devel] [PATCH V3 for-1.6 3/5] block: Add support for throttling burst threshold in QMP and the co mmand line., Benoît Canet, 2013/07/23
- [Qemu-devel] [PATCH V3 for-1.6 2/5] block: Modify the throttling code to implement the leaky bucket algorithm., Benoît Canet, 2013/07/23
- [Qemu-devel] [PATCH V3 for-1.6 4/5] block: Add iops_sector_count to do the iops accounting for a gi ven io size., Benoît Canet, 2013/07/23
- [Qemu-devel] [PATCH V3 for-1.6 5/5] block: Add throttling percentage metrics., Benoît Canet, 2013/07/23
- Re: [Qemu-devel] [PATCH V3 for-1.6 0/5] Leaky bucket throttling and features, Fam Zheng, 2013/07/25
- Re: [Qemu-devel] [PATCH V3 for-1.6 0/5] Leaky bucket throttling and features, Eric Blake, 2013/07/26