| Message ID | 1314877456-19521-4-git-send-email-wuzhy@linux.vnet.ibm.com |
|---|---|
| State | New |
| Headers | show |
On Thu, Sep 1, 2011 at 12:44 PM, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> wrote: > Note: > 1.) When bps/iops limits are specified to a small value such as 511 bytes/s, this VM will hang up. We are considering how to handle this senario. > 2.) When "dd" command is issued in guest, if its option bs is set to a large value such as "bs=1024K", the result speed will slightly bigger than the limits. > > For these problems, if you have nice thought, pls let us know.:) > > Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> > --- > block.c | 290 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- > block.h | 5 + > block_int.h | 9 ++ > 3 files changed, 296 insertions(+), 8 deletions(-) > > diff --git a/block.c b/block.c > index 17ee3df..680f1e7 100644 > --- a/block.c > +++ b/block.c > @@ -30,6 +30,9 @@ > #include "qemu-objects.h" > #include "qemu-coroutine.h" > > +#include "qemu-timer.h" > +#include "block/blk-queue.h" > + > #ifdef CONFIG_BSD > #include <sys/types.h> > #include <sys/stat.h> > @@ -72,6 +75,13 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, > QEMUIOVector *iov); > static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs); > > +static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors, > + bool is_write, double elapsed_time, uint64_t *wait); > +static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write, > + double elapsed_time, uint64_t *wait); > +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, > + bool is_write, uint64_t *wait); > + > static QTAILQ_HEAD(, BlockDriverState) bdrv_states = > QTAILQ_HEAD_INITIALIZER(bdrv_states); > > @@ -104,6 +114,64 @@ int is_windows_drive(const char *filename) > } > #endif > > +/* throttling disk I/O limits */ > +void bdrv_io_limits_disable(BlockDriverState *bs) > +{ > + bs->io_limits_enabled = false; > + > + if (bs->block_queue) { > + qemu_block_queue_flush(bs->block_queue); > + qemu_del_block_queue(bs->block_queue); > + bs->block_queue = NULL; > + } > + > + if (bs->block_timer) { > + qemu_del_timer(bs->block_timer); > + qemu_free_timer(bs->block_timer); > + bs->block_timer = NULL; > + } > + > + bs->slice_start[BLOCK_IO_LIMIT_READ] = 0; > + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = 0; > + > + bs->slice_end[BLOCK_IO_LIMIT_READ] = 0; > + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = 0; > +} > + > +static void bdrv_block_timer(void *opaque) > +{ > + BlockDriverState *bs = opaque; > + BlockQueue *queue = bs->block_queue; > + > + qemu_block_queue_flush(queue); > +} > + > +void bdrv_io_limits_enable(BlockDriverState *bs) > +{ > + bs->block_queue = qemu_new_block_queue(); > + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs); > + > + bs->slice_start[BLOCK_IO_LIMIT_READ] = qemu_get_clock_ns(vm_clock); > + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = > + bs->slice_start[BLOCK_IO_LIMIT_READ]; > + > + bs->slice_end[BLOCK_IO_LIMIT_READ] = > + bs->slice_start[BLOCK_IO_LIMIT_READ] + BLOCK_IO_SLICE_TIME; > + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = > + bs->slice_end[BLOCK_IO_LIMIT_READ]; > +} > + > +bool bdrv_io_limits_enabled(BlockDriverState *bs) > +{ > + BlockIOLimit *io_limits = &bs->io_limits; > + return io_limits->bps[BLOCK_IO_LIMIT_READ] > + || io_limits->bps[BLOCK_IO_LIMIT_WRITE] > + || io_limits->bps[BLOCK_IO_LIMIT_TOTAL] > + || io_limits->iops[BLOCK_IO_LIMIT_READ] > + || io_limits->iops[BLOCK_IO_LIMIT_WRITE] > + || io_limits->iops[BLOCK_IO_LIMIT_TOTAL]; > +} > + > /* check if the path starts with "<protocol>:" */ > static int path_has_protocol(const char *path) > { > @@ -694,6 +762,11 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, > bs->change_cb(bs->change_opaque, CHANGE_MEDIA); > } > > + /* throttling disk I/O limits */ > + if (bs->io_limits_enabled) { > + bdrv_io_limits_enable(bs); > + } > + > return 0; > > unlink_and_fail: > @@ -732,6 +805,18 @@ void bdrv_close(BlockDriverState *bs) > if (bs->change_cb) > bs->change_cb(bs->change_opaque, CHANGE_MEDIA); > } > + > + /* throttling disk I/O limits */ > + if (bs->block_queue) { > + qemu_del_block_queue(bs->block_queue); > + bs->block_queue = NULL; > + } > + > + if (bs->block_timer) { > + qemu_del_timer(bs->block_timer); > + qemu_free_timer(bs->block_timer); > + bs->block_timer = NULL; > + } > } > > void bdrv_close_all(void) > @@ -2290,13 +2375,29 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, > BlockDriverCompletionFunc *cb, void *opaque) > { > BlockDriver *drv = bs->drv; > + uint64_t wait_time = 0; > + BlockDriverAIOCB *ret; > > trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); > > - if (!drv) > - return NULL; > - if (bdrv_check_request(bs, sector_num, nb_sectors)) > + if (!drv || bdrv_check_request(bs, sector_num, nb_sectors)) { > return NULL; > + } > + > + /* throttling disk read I/O */ > + if (bs->io_limits_enabled) { > + if (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) { > + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_readv, > + sector_num, qiov, nb_sectors, cb, opaque); > + qemu_mod_timer(bs->block_timer, > + wait_time + qemu_get_clock_ns(vm_clock)); > + return ret; > + } > + > + bs->io_disps.bytes[BLOCK_IO_LIMIT_READ] += > + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; > + bs->io_disps.ios[BLOCK_IO_LIMIT_READ]++; > + } > > return drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors, > cb, opaque); > @@ -2345,15 +2446,14 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, > BlockDriver *drv = bs->drv; > BlockDriverAIOCB *ret; > BlockCompleteData *blk_cb_data; > + uint64_t wait_time = 0; > > trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); > > - if (!drv) > - return NULL; > - if (bs->read_only) > - return NULL; > - if (bdrv_check_request(bs, sector_num, nb_sectors)) > + if (!drv || bs->read_only > + || bdrv_check_request(bs, sector_num, nb_sectors)) { > return NULL; > + } > > if (bs->dirty_bitmap) { > blk_cb_data = blk_dirty_cb_alloc(bs, sector_num, nb_sectors, cb, > @@ -2362,6 +2462,17 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, > opaque = blk_cb_data; > } > > + /* throttling disk write I/O */ > + if (bs->io_limits_enabled) { > + if (bdrv_exceed_io_limits(bs, nb_sectors, true, &wait_time)) { > + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_writev, > + sector_num, qiov, nb_sectors, cb, opaque); > + qemu_mod_timer(bs->block_timer, > + wait_time + qemu_get_clock_ns(vm_clock)); > + return ret; > + } > + } > + > ret = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, > cb, opaque); > > @@ -2369,6 +2480,12 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, > if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { > bs->wr_highest_sector = sector_num + nb_sectors - 1; > } > + > + if (bs->io_limits_enabled) { > + bs->io_disps.bytes[BLOCK_IO_LIMIT_WRITE] += > + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; > + bs->io_disps.ios[BLOCK_IO_LIMIT_WRITE]++; > + } > } > > return ret; > @@ -2633,6 +2750,163 @@ void bdrv_aio_cancel(BlockDriverAIOCB *acb) > acb->pool->cancel(acb); > } > > +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; > + double bytes_limit, bytes_disp, 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[is_write] - bs->slice_start[is_write]; > + slice_time /= (NANOSECONDS_PER_SECOND); > + bytes_limit = bps_limit * slice_time; > + bytes_disp = bs->io_disps.bytes[is_write]; > + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) { > + bytes_disp += bs->io_disps.bytes[!is_write]; > + } > + > + bytes_res = (unsigned) nb_sectors * BDRV_SECTOR_SIZE; > + > + if (bytes_disp + bytes_res <= bytes_limit) { > + if (wait) { > + *wait = 0; > + } > + > + return false; > + } > + > + /* Calc approx time to dispatch */ > + wait_time = (bytes_disp + bytes_res) / bps_limit - elapsed_time; > + > + if (wait) { > + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; > + } > + > + 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_disp; > + 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[is_write] - bs->slice_start[is_write]; > + slice_time /= (NANOSECONDS_PER_SECOND); > + ios_limit = iops_limit * slice_time; > + ios_disp = bs->io_disps.ios[is_write]; > + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { > + ios_disp += bs->io_disps.ios[!is_write]; > + } > + > + if (ios_disp + 1 <= ios_limit) { > + if (wait) { > + *wait = 0; > + } > + > + return false; > + } > + > + /* Calc approx time to dispatch */ > + wait_time = (ios_disp + 1) / iops_limit; > + if (wait_time > elapsed_time) { > + wait_time = wait_time - elapsed_time; > + } else { > + wait_time = 0; > + } > + > + if (wait) { > + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; > + } > + > + return true; > +} > + > +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, > + bool is_write, uint64_t *wait) { > + int64_t now; > + uint64_t bps_wait = 0, iops_wait = 0, max_wait; > + double elapsed_time; > + int bps_ret, iops_ret; > + > + now = qemu_get_clock_ns(vm_clock); > + if ((bs->slice_start[is_write] < now) > + && (bs->slice_end[is_write] > now)) { > + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; > + } else { > + bs->slice_start[is_write] = now; > + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; > + > + bs->io_disps.bytes[is_write] = 0; > + bs->io_disps.bytes[!is_write] = 0; > + > + bs->io_disps.ios[is_write] = 0; > + bs->io_disps.ios[!is_write] = 0; Does it make sense to keep separate slice_start/slice_end for read and write since we reset the dispatched statistics to zero for both? Perhaps we should use a scalar slice_start/slice_end and not two separate values for read/write. > + } > + > + /* If a limit was exceeded, immediately queue this request */ > + if (qemu_block_queue_has_pending(bs->block_queue)) { > + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL] > + || bs->io_limits.bps[is_write] || bs->io_limits.iops[is_write] > + || bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { > + if (wait) { > + *wait = 0; This causes the queue to be flushed each time the guest enqueues an I/O while there are queued requests. Perhaps this is (part of) the CPU overhead that Ryan's benchmarking discovered. If we try to preserve request ordering then I don't think there is a reason to modify the timer once it has been set. Stefan
On Thu, Sep 01, 2011 at 02:36:41PM +0100, Stefan Hajnoczi wrote: >Date: Thu, 1 Sep 2011 14:36:41 +0100 >Message-ID: <CAJSP0QU8GqWsA6jaYAfs0=hvabQayfRPSzRNctGP6GEGgptHaw@mail.gmail.com> >From: Stefan Hajnoczi <stefanha@gmail.com> >To: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> >Content-Type: text/plain; charset=ISO-8859-1 >Content-Transfer-Encoding: quoted-printable >X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.6 (newer, 2) >X-Received-From: 209.85.216.45 >Cc: kwolf@redhat.com, aliguori@us.ibm.com, stefanha@linux.vnet.ibm.com, > kvm@vger.kernel.org, mtosatti@redhat.com, qemu-devel@nongnu.org, > pair@us.ibm.com, zwu.kernel@gmail.com, ryanh@us.ibm.com >Subject: Re: [Qemu-devel] [PATCH v6 3/4] block: add block timer and block > throttling algorithm >X-BeenThere: qemu-devel@nongnu.org >X-Mailman-Version: 2.1.14 >Precedence: list >List-Id: <qemu-devel.nongnu.org> >List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>, > <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe> >List-Archive: </archive/html/qemu-devel> >List-Post: <mailto:qemu-devel@nongnu.org> >List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help> >List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>, > <mailto:qemu-devel-request@nongnu.org?subject=subscribe> >X-Mailman-Copy: yes >Errors-To: qemu-devel-bounces+wuzhy=linux.vnet.ibm.com@nongnu.org >Sender: qemu-devel-bounces+wuzhy=linux.vnet.ibm.com@nongnu.org >X-Brightmail-Tracker: AAAAAA== >X-Xagent-From: stefanha@gmail.com >X-Xagent-To: wuzhy@linux.vnet.ibm.com >X-Xagent-Gateway: bldgate.vnet.ibm.com (XAGENTU8 at BLDGATE) > >On Thu, Sep 1, 2011 at 12:44 PM, Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> wrote: >> Note: >> 1.) When bps/iops limits are specified to a small value such as 511 bytes/s, this VM will hang up. We are considering how to handle this senario. >> 2.) When "dd" command is issued in guest, if its option bs is set to a large value such as "bs=1024K", the result speed will slightly bigger than the limits. >> >> For these problems, if you have nice thought, pls let us know.:) >> >> Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> >> --- >> block.c | 290 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- >> block.h | 5 + >> block_int.h | 9 ++ >> 3 files changed, 296 insertions(+), 8 deletions(-) >> >> diff --git a/block.c b/block.c >> index 17ee3df..680f1e7 100644 >> --- a/block.c >> +++ b/block.c >> @@ -30,6 +30,9 @@ >> #include "qemu-objects.h" >> #include "qemu-coroutine.h" >> >> +#include "qemu-timer.h" >> +#include "block/blk-queue.h" >> + >> #ifdef CONFIG_BSD >> #include <sys/types.h> >> #include <sys/stat.h> >> @@ -72,6 +75,13 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, >> QEMUIOVector *iov); >> static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs); >> >> +static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors, >> + bool is_write, double elapsed_time, uint64_t *wait); >> +static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write, >> + double elapsed_time, uint64_t *wait); >> +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, >> + bool is_write, uint64_t *wait); >> + >> static QTAILQ_HEAD(, BlockDriverState) bdrv_states = >> QTAILQ_HEAD_INITIALIZER(bdrv_states); >> >> @@ -104,6 +114,64 @@ int is_windows_drive(const char *filename) >> } >> #endif >> >> +/* throttling disk I/O limits */ >> +void bdrv_io_limits_disable(BlockDriverState *bs) >> +{ >> + bs->io_limits_enabled = false; >> + >> + if (bs->block_queue) { >> + qemu_block_queue_flush(bs->block_queue); >> + qemu_del_block_queue(bs->block_queue); >> + bs->block_queue = NULL; >> + } >> + >> + if (bs->block_timer) { >> + qemu_del_timer(bs->block_timer); >> + qemu_free_timer(bs->block_timer); >> + bs->block_timer = NULL; >> + } >> + >> + bs->slice_start[BLOCK_IO_LIMIT_READ] = 0; >> + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = 0; >> + >> + bs->slice_end[BLOCK_IO_LIMIT_READ] = 0; >> + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = 0; >> +} >> + >> +static void bdrv_block_timer(void *opaque) >> +{ >> + BlockDriverState *bs = opaque; >> + BlockQueue *queue = bs->block_queue; >> + >> + qemu_block_queue_flush(queue); >> +} >> + >> +void bdrv_io_limits_enable(BlockDriverState *bs) >> +{ >> + bs->block_queue = qemu_new_block_queue(); >> + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs); >> + >> + bs->slice_start[BLOCK_IO_LIMIT_READ] = qemu_get_clock_ns(vm_clock); >> + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = >> + bs->slice_start[BLOCK_IO_LIMIT_READ]; >> + >> + bs->slice_end[BLOCK_IO_LIMIT_READ] = >> + bs->slice_start[BLOCK_IO_LIMIT_READ] + BLOCK_IO_SLICE_TIME; >> + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = >> + bs->slice_end[BLOCK_IO_LIMIT_READ]; >> +} >> + >> +bool bdrv_io_limits_enabled(BlockDriverState *bs) >> +{ >> + BlockIOLimit *io_limits = &bs->io_limits; >> + return io_limits->bps[BLOCK_IO_LIMIT_READ] >> + || io_limits->bps[BLOCK_IO_LIMIT_WRITE] >> + || io_limits->bps[BLOCK_IO_LIMIT_TOTAL] >> + || io_limits->iops[BLOCK_IO_LIMIT_READ] >> + || io_limits->iops[BLOCK_IO_LIMIT_WRITE] >> + || io_limits->iops[BLOCK_IO_LIMIT_TOTAL]; >> +} >> + >> /* check if the path starts with "<protocol>:" */ >> static int path_has_protocol(const char *path) >> { >> @@ -694,6 +762,11 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, >> bs->change_cb(bs->change_opaque, CHANGE_MEDIA); >> } >> >> + /* throttling disk I/O limits */ >> + if (bs->io_limits_enabled) { >> + bdrv_io_limits_enable(bs); >> + } >> + >> return 0; >> >> unlink_and_fail: >> @@ -732,6 +805,18 @@ void bdrv_close(BlockDriverState *bs) >> if (bs->change_cb) >> bs->change_cb(bs->change_opaque, CHANGE_MEDIA); >> } >> + >> + /* throttling disk I/O limits */ >> + if (bs->block_queue) { >> + qemu_del_block_queue(bs->block_queue); >> + bs->block_queue = NULL; >> + } >> + >> + if (bs->block_timer) { >> + qemu_del_timer(bs->block_timer); >> + qemu_free_timer(bs->block_timer); >> + bs->block_timer = NULL; >> + } >> } >> >> void bdrv_close_all(void) >> @@ -2290,13 +2375,29 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, >> BlockDriverCompletionFunc *cb, void *opaque) >> { >> BlockDriver *drv = bs->drv; >> + uint64_t wait_time = 0; >> + BlockDriverAIOCB *ret; >> >> trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); >> >> - if (!drv) >> - return NULL; >> - if (bdrv_check_request(bs, sector_num, nb_sectors)) >> + if (!drv || bdrv_check_request(bs, sector_num, nb_sectors)) { >> return NULL; >> + } >> + >> + /* throttling disk read I/O */ >> + if (bs->io_limits_enabled) { >> + if (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) { >> + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_readv, >> + sector_num, qiov, nb_sectors, cb, opaque); >> + qemu_mod_timer(bs->block_timer, >> + wait_time + qemu_get_clock_ns(vm_clock)); >> + return ret; >> + } >> + >> + bs->io_disps.bytes[BLOCK_IO_LIMIT_READ] += >> + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; >> + bs->io_disps.ios[BLOCK_IO_LIMIT_READ]++; >> + } >> >> return drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors, >> cb, opaque); >> @@ -2345,15 +2446,14 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, >> BlockDriver *drv = bs->drv; >> BlockDriverAIOCB *ret; >> BlockCompleteData *blk_cb_data; >> + uint64_t wait_time = 0; >> >> trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); >> >> - if (!drv) >> - return NULL; >> - if (bs->read_only) >> - return NULL; >> - if (bdrv_check_request(bs, sector_num, nb_sectors)) >> + if (!drv || bs->read_only >> + || bdrv_check_request(bs, sector_num, nb_sectors)) { >> return NULL; >> + } >> >> if (bs->dirty_bitmap) { >> blk_cb_data = blk_dirty_cb_alloc(bs, sector_num, nb_sectors, cb, >> @@ -2362,6 +2462,17 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, >> opaque = blk_cb_data; >> } >> >> + /* throttling disk write I/O */ >> + if (bs->io_limits_enabled) { >> + if (bdrv_exceed_io_limits(bs, nb_sectors, true, &wait_time)) { >> + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_writev, >> + sector_num, qiov, nb_sectors, cb, opaque); >> + qemu_mod_timer(bs->block_timer, >> + wait_time + qemu_get_clock_ns(vm_clock)); >> + return ret; >> + } >> + } >> + >> ret = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, >> cb, opaque); >> >> @@ -2369,6 +2480,12 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, >> if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { >> bs->wr_highest_sector = sector_num + nb_sectors - 1; >> } >> + >> + if (bs->io_limits_enabled) { >> + bs->io_disps.bytes[BLOCK_IO_LIMIT_WRITE] += >> + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; >> + bs->io_disps.ios[BLOCK_IO_LIMIT_WRITE]++; >> + } >> } >> >> return ret; >> @@ -2633,6 +2750,163 @@ void bdrv_aio_cancel(BlockDriverAIOCB *acb) >> acb->pool->cancel(acb); >> } >> >> +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; >> + double bytes_limit, bytes_disp, 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[is_write] - bs->slice_start[is_write]; >> + slice_time /= (NANOSECONDS_PER_SECOND); >> + bytes_limit = bps_limit * slice_time; >> + bytes_disp = bs->io_disps.bytes[is_write]; >> + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) { >> + bytes_disp += bs->io_disps.bytes[!is_write]; >> + } >> + >> + bytes_res = (unsigned) nb_sectors * BDRV_SECTOR_SIZE; >> + >> + if (bytes_disp + bytes_res <= bytes_limit) { >> + if (wait) { >> + *wait = 0; >> + } >> + >> + return false; >> + } >> + >> + /* Calc approx time to dispatch */ >> + wait_time = (bytes_disp + bytes_res) / bps_limit - elapsed_time; >> + >> + if (wait) { >> + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; >> + } >> + >> + 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_disp; >> + 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[is_write] - bs->slice_start[is_write]; >> + slice_time /= (NANOSECONDS_PER_SECOND); >> + ios_limit = iops_limit * slice_time; >> + ios_disp = bs->io_disps.ios[is_write]; >> + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { >> + ios_disp += bs->io_disps.ios[!is_write]; >> + } >> + >> + if (ios_disp + 1 <= ios_limit) { >> + if (wait) { >> + *wait = 0; >> + } >> + >> + return false; >> + } >> + >> + /* Calc approx time to dispatch */ >> + wait_time = (ios_disp + 1) / iops_limit; >> + if (wait_time > elapsed_time) { >> + wait_time = wait_time - elapsed_time; >> + } else { >> + wait_time = 0; >> + } >> + >> + if (wait) { >> + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; >> + } >> + >> + return true; >> +} >> + >> +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, >> + bool is_write, uint64_t *wait) { >> + int64_t now; >> + uint64_t bps_wait = 0, iops_wait = 0, max_wait; >> + double elapsed_time; >> + int bps_ret, iops_ret; >> + >> + now = qemu_get_clock_ns(vm_clock); >> + if ((bs->slice_start[is_write] < now) >> + && (bs->slice_end[is_write] > now)) { >> + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; >> + } else { >> + bs->slice_start[is_write] = now; >> + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; >> + >> + bs->io_disps.bytes[is_write] = 0; >> + bs->io_disps.bytes[!is_write] = 0; >> + >> + bs->io_disps.ios[is_write] = 0; >> + bs->io_disps.ios[!is_write] = 0; > >Does it make sense to keep separate slice_start/slice_end for read and >write since we reset the dispatched statistics to zero for both? >Perhaps we should use a scalar slice_start/slice_end and not two >separate values for read/write. Right, currently the scalar slice_* should be adopted, thanks. > >> + } >> + >> + /* If a limit was exceeded, immediately queue this request */ >> + if (qemu_block_queue_has_pending(bs->block_queue)) { >> + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL] >> + || bs->io_limits.bps[is_write] || bs->io_limits.iops[is_write] >> + || bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { >> + if (wait) { >> + *wait = 0; > >This causes the queue to be flushed each time the guest enqueues an >I/O while there are queued requests. Perhaps this is (part of) the >CPU overhead that Ryan's benchmarking discovered. > >If we try to preserve request ordering then I don't think there is a >reason to modify the timer once it has been set. good catch, pls check the latest changes on my public git branch. > >Stefan >
diff --git a/block.c b/block.c index 17ee3df..680f1e7 100644 --- a/block.c +++ b/block.c @@ -30,6 +30,9 @@ #include "qemu-objects.h" #include "qemu-coroutine.h" +#include "qemu-timer.h" +#include "block/blk-queue.h" + #ifdef CONFIG_BSD #include <sys/types.h> #include <sys/stat.h> @@ -72,6 +75,13 @@ static int coroutine_fn bdrv_co_writev_em(BlockDriverState *bs, QEMUIOVector *iov); static int coroutine_fn bdrv_co_flush_em(BlockDriverState *bs); +static bool bdrv_exceed_bps_limits(BlockDriverState *bs, int nb_sectors, + bool is_write, double elapsed_time, uint64_t *wait); +static bool bdrv_exceed_iops_limits(BlockDriverState *bs, bool is_write, + double elapsed_time, uint64_t *wait); +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, + bool is_write, uint64_t *wait); + static QTAILQ_HEAD(, BlockDriverState) bdrv_states = QTAILQ_HEAD_INITIALIZER(bdrv_states); @@ -104,6 +114,64 @@ int is_windows_drive(const char *filename) } #endif +/* throttling disk I/O limits */ +void bdrv_io_limits_disable(BlockDriverState *bs) +{ + bs->io_limits_enabled = false; + + if (bs->block_queue) { + qemu_block_queue_flush(bs->block_queue); + qemu_del_block_queue(bs->block_queue); + bs->block_queue = NULL; + } + + if (bs->block_timer) { + qemu_del_timer(bs->block_timer); + qemu_free_timer(bs->block_timer); + bs->block_timer = NULL; + } + + bs->slice_start[BLOCK_IO_LIMIT_READ] = 0; + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = 0; + + bs->slice_end[BLOCK_IO_LIMIT_READ] = 0; + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = 0; +} + +static void bdrv_block_timer(void *opaque) +{ + BlockDriverState *bs = opaque; + BlockQueue *queue = bs->block_queue; + + qemu_block_queue_flush(queue); +} + +void bdrv_io_limits_enable(BlockDriverState *bs) +{ + bs->block_queue = qemu_new_block_queue(); + bs->block_timer = qemu_new_timer_ns(vm_clock, bdrv_block_timer, bs); + + bs->slice_start[BLOCK_IO_LIMIT_READ] = qemu_get_clock_ns(vm_clock); + bs->slice_start[BLOCK_IO_LIMIT_WRITE] = + bs->slice_start[BLOCK_IO_LIMIT_READ]; + + bs->slice_end[BLOCK_IO_LIMIT_READ] = + bs->slice_start[BLOCK_IO_LIMIT_READ] + BLOCK_IO_SLICE_TIME; + bs->slice_end[BLOCK_IO_LIMIT_WRITE] = + bs->slice_end[BLOCK_IO_LIMIT_READ]; +} + +bool bdrv_io_limits_enabled(BlockDriverState *bs) +{ + BlockIOLimit *io_limits = &bs->io_limits; + return io_limits->bps[BLOCK_IO_LIMIT_READ] + || io_limits->bps[BLOCK_IO_LIMIT_WRITE] + || io_limits->bps[BLOCK_IO_LIMIT_TOTAL] + || io_limits->iops[BLOCK_IO_LIMIT_READ] + || io_limits->iops[BLOCK_IO_LIMIT_WRITE] + || io_limits->iops[BLOCK_IO_LIMIT_TOTAL]; +} + /* check if the path starts with "<protocol>:" */ static int path_has_protocol(const char *path) { @@ -694,6 +762,11 @@ int bdrv_open(BlockDriverState *bs, const char *filename, int flags, bs->change_cb(bs->change_opaque, CHANGE_MEDIA); } + /* throttling disk I/O limits */ + if (bs->io_limits_enabled) { + bdrv_io_limits_enable(bs); + } + return 0; unlink_and_fail: @@ -732,6 +805,18 @@ void bdrv_close(BlockDriverState *bs) if (bs->change_cb) bs->change_cb(bs->change_opaque, CHANGE_MEDIA); } + + /* throttling disk I/O limits */ + if (bs->block_queue) { + qemu_del_block_queue(bs->block_queue); + bs->block_queue = NULL; + } + + if (bs->block_timer) { + qemu_del_timer(bs->block_timer); + qemu_free_timer(bs->block_timer); + bs->block_timer = NULL; + } } void bdrv_close_all(void) @@ -2290,13 +2375,29 @@ BlockDriverAIOCB *bdrv_aio_readv(BlockDriverState *bs, int64_t sector_num, BlockDriverCompletionFunc *cb, void *opaque) { BlockDriver *drv = bs->drv; + uint64_t wait_time = 0; + BlockDriverAIOCB *ret; trace_bdrv_aio_readv(bs, sector_num, nb_sectors, opaque); - if (!drv) - return NULL; - if (bdrv_check_request(bs, sector_num, nb_sectors)) + if (!drv || bdrv_check_request(bs, sector_num, nb_sectors)) { return NULL; + } + + /* throttling disk read I/O */ + if (bs->io_limits_enabled) { + if (bdrv_exceed_io_limits(bs, nb_sectors, false, &wait_time)) { + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_readv, + sector_num, qiov, nb_sectors, cb, opaque); + qemu_mod_timer(bs->block_timer, + wait_time + qemu_get_clock_ns(vm_clock)); + return ret; + } + + bs->io_disps.bytes[BLOCK_IO_LIMIT_READ] += + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; + bs->io_disps.ios[BLOCK_IO_LIMIT_READ]++; + } return drv->bdrv_aio_readv(bs, sector_num, qiov, nb_sectors, cb, opaque); @@ -2345,15 +2446,14 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, BlockDriver *drv = bs->drv; BlockDriverAIOCB *ret; BlockCompleteData *blk_cb_data; + uint64_t wait_time = 0; trace_bdrv_aio_writev(bs, sector_num, nb_sectors, opaque); - if (!drv) - return NULL; - if (bs->read_only) - return NULL; - if (bdrv_check_request(bs, sector_num, nb_sectors)) + if (!drv || bs->read_only + || bdrv_check_request(bs, sector_num, nb_sectors)) { return NULL; + } if (bs->dirty_bitmap) { blk_cb_data = blk_dirty_cb_alloc(bs, sector_num, nb_sectors, cb, @@ -2362,6 +2462,17 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, opaque = blk_cb_data; } + /* throttling disk write I/O */ + if (bs->io_limits_enabled) { + if (bdrv_exceed_io_limits(bs, nb_sectors, true, &wait_time)) { + ret = qemu_block_queue_enqueue(bs->block_queue, bs, bdrv_aio_writev, + sector_num, qiov, nb_sectors, cb, opaque); + qemu_mod_timer(bs->block_timer, + wait_time + qemu_get_clock_ns(vm_clock)); + return ret; + } + } + ret = drv->bdrv_aio_writev(bs, sector_num, qiov, nb_sectors, cb, opaque); @@ -2369,6 +2480,12 @@ BlockDriverAIOCB *bdrv_aio_writev(BlockDriverState *bs, int64_t sector_num, if (bs->wr_highest_sector < sector_num + nb_sectors - 1) { bs->wr_highest_sector = sector_num + nb_sectors - 1; } + + if (bs->io_limits_enabled) { + bs->io_disps.bytes[BLOCK_IO_LIMIT_WRITE] += + (unsigned) nb_sectors * BDRV_SECTOR_SIZE; + bs->io_disps.ios[BLOCK_IO_LIMIT_WRITE]++; + } } return ret; @@ -2633,6 +2750,163 @@ void bdrv_aio_cancel(BlockDriverAIOCB *acb) acb->pool->cancel(acb); } +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; + double bytes_limit, bytes_disp, 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[is_write] - bs->slice_start[is_write]; + slice_time /= (NANOSECONDS_PER_SECOND); + bytes_limit = bps_limit * slice_time; + bytes_disp = bs->io_disps.bytes[is_write]; + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL]) { + bytes_disp += bs->io_disps.bytes[!is_write]; + } + + bytes_res = (unsigned) nb_sectors * BDRV_SECTOR_SIZE; + + if (bytes_disp + bytes_res <= bytes_limit) { + if (wait) { + *wait = 0; + } + + return false; + } + + /* Calc approx time to dispatch */ + wait_time = (bytes_disp + bytes_res) / bps_limit - elapsed_time; + + if (wait) { + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; + } + + 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_disp; + 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[is_write] - bs->slice_start[is_write]; + slice_time /= (NANOSECONDS_PER_SECOND); + ios_limit = iops_limit * slice_time; + ios_disp = bs->io_disps.ios[is_write]; + if (bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { + ios_disp += bs->io_disps.ios[!is_write]; + } + + if (ios_disp + 1 <= ios_limit) { + if (wait) { + *wait = 0; + } + + return false; + } + + /* Calc approx time to dispatch */ + wait_time = (ios_disp + 1) / iops_limit; + if (wait_time > elapsed_time) { + wait_time = wait_time - elapsed_time; + } else { + wait_time = 0; + } + + if (wait) { + *wait = wait_time * BLOCK_IO_SLICE_TIME * 10; + } + + return true; +} + +static bool bdrv_exceed_io_limits(BlockDriverState *bs, int nb_sectors, + bool is_write, uint64_t *wait) { + int64_t now; + uint64_t bps_wait = 0, iops_wait = 0, max_wait; + double elapsed_time; + int bps_ret, iops_ret; + + now = qemu_get_clock_ns(vm_clock); + if ((bs->slice_start[is_write] < now) + && (bs->slice_end[is_write] > now)) { + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; + } else { + bs->slice_start[is_write] = now; + bs->slice_end[is_write] = now + BLOCK_IO_SLICE_TIME; + + bs->io_disps.bytes[is_write] = 0; + bs->io_disps.bytes[!is_write] = 0; + + bs->io_disps.ios[is_write] = 0; + bs->io_disps.ios[!is_write] = 0; + } + + /* If a limit was exceeded, immediately queue this request */ + if (qemu_block_queue_has_pending(bs->block_queue)) { + if (bs->io_limits.bps[BLOCK_IO_LIMIT_TOTAL] + || bs->io_limits.bps[is_write] || bs->io_limits.iops[is_write] + || bs->io_limits.iops[BLOCK_IO_LIMIT_TOTAL]) { + if (wait) { + *wait = 0; + } + + return true; + } + } + + elapsed_time = now - bs->slice_start[is_write]; + 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[is_write] < now + max_wait) { + bs->slice_end[is_write] = now + max_wait; + } + + return true; + } + + if (wait) { + *wait = 0; + } + + return false; +} /**************************************************************/ /* async block device emulation */ diff --git a/block.h b/block.h index 3ac0b94..a3e69db 100644 --- a/block.h +++ b/block.h @@ -58,6 +58,11 @@ void bdrv_info(Monitor *mon, QObject **ret_data); void bdrv_stats_print(Monitor *mon, const QObject *data); void bdrv_info_stats(Monitor *mon, QObject **ret_data); +/* disk I/O throttling */ +void bdrv_io_limits_enable(BlockDriverState *bs); +void bdrv_io_limits_disable(BlockDriverState *bs); +bool bdrv_io_limits_enabled(BlockDriverState *bs); + void bdrv_init(void); void bdrv_init_with_whitelist(void); BlockDriver *bdrv_find_protocol(const char *filename); diff --git a/block_int.h b/block_int.h index e7bda5b..5d37277 100644 --- a/block_int.h +++ b/block_int.h @@ -202,6 +202,15 @@ struct BlockDriverState { void *sync_aiocb; + /* the time for latest disk I/O */ + int64_t slice_start[2]; + int64_t slice_end[2]; + BlockIOLimit io_limits; + BlockIODisp io_disps; + BlockQueue *block_queue; + QEMUTimer *block_timer; + bool io_limits_enabled; + /* I/O stats (display with "info blockstats"). */ uint64_t nr_bytes[BDRV_MAX_IOTYPE]; uint64_t nr_ops[BDRV_MAX_IOTYPE];
Note: 1.) When bps/iops limits are specified to a small value such as 511 bytes/s, this VM will hang up. We are considering how to handle this senario. 2.) When "dd" command is issued in guest, if its option bs is set to a large value such as "bs=1024K", the result speed will slightly bigger than the limits. For these problems, if you have nice thought, pls let us know.:) Signed-off-by: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com> --- block.c | 290 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++-- block.h | 5 + block_int.h | 9 ++ 3 files changed, 296 insertions(+), 8 deletions(-)