Re: [Qemu-devel] [PATCH v2 1/1] The codes V2 for QEMU disk I/O limits.

[Zhi Yong Wu]

On Thu, Jul 28, 2011 at 4:25 PM, Stefan Hajnoczi <address@hidden> wrote:
> On Thu, Jul 28, 2011 at 9:20 AM, Stefan Hajnoczi <address@hidden> wrote:
>> On Thu, Jul 28, 2011 at 6:43 AM, Zhi Yong Wu <address@hidden> wrote:
>>> On Wed, Jul 27, 2011 at 8:58 PM, Stefan Hajnoczi <address@hidden> wrote:
>>>> On Wed, Jul 27, 2011 at 11:17 AM, Zhi Yong Wu <address@hidden> wrote:
>>>>> On Wed, Jul 27, 2011 at 3:26 AM, Marcelo Tosatti <address@hidden> wrote:
>>>>>> On Tue, Jul 26, 2011 at 04:59:06PM +0800, Zhi Yong Wu wrote:
>>>>>>> Welcome to give me your comments, thanks.
>>>>>>>
>>>>>>> Signed-off-by: Zhi Yong Wu <address@hidden>
>>>>>>> ---
>>>>>>>  Makefile.objs     |    2 +-
>>>>>>>  block.c           |  288 
>>>>>>> +++++++++++++++++++++++++++++++++++++++++++++++++++--
>>>>>>>  block.h           |    1 -
>>>>>>>  block/blk-queue.c |  116 +++++++++++++++++++++
>>>>>>>  block/blk-queue.h |   70 +++++++++++++
>>>>>>>  block_int.h       |   28 +++++
>>>>>>>  blockdev.c        |   21 ++++
>>>>>>>  qemu-config.c     |   24 +++++
>>>>>>>  qemu-option.c     |   17 +++
>>>>>>>  qemu-option.h     |    1 +
>>>>>>>  qemu-options.hx   |    1 +
>>>>>>>  11 files changed, 559 insertions(+), 10 deletions(-)
>>>>>>>  create mode 100644 block/blk-queue.c
>>>>>>>  create mode 100644 block/blk-queue.h
>>>>>>>
>>>>>>> diff --git a/Makefile.objs b/Makefile.objs
>>>>>>> index 9f99ed4..06f2033 100644
>>>>>>> --- a/Makefile.objs
>>>>>>> +++ b/Makefile.objs
>>>>>>> @@ -23,7 +23,7 @@ block-nested-y += raw.o cow.o qcow.o vdi.o vmdk.o 
>>>>>>> cloop.o dmg.o bochs.o vpc.o vv
>>>>>>>  block-nested-y += qcow2.o qcow2-refcount.o qcow2-cluster.o 
>>>>>>> qcow2-snapshot.o qcow2-cache.o
>>>>>>>  block-nested-y += qed.o qed-gencb.o qed-l2-cache.o qed-table.o 
>>>>>>> qed-cluster.o
>>>>>>>  block-nested-y += qed-check.o
>>>>>>> -block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o
>>>>>>> +block-nested-y += parallels.o nbd.o blkdebug.o sheepdog.o blkverify.o 
>>>>>>> blk-queue.o
>>>>>>>  block-nested-$(CONFIG_WIN32) += raw-win32.o
>>>>>>>  block-nested-$(CONFIG_POSIX) += raw-posix.o
>>>>>>>  block-nested-$(CONFIG_CURL) += curl.o
>>>>>>> diff --git a/block.c b/block.c
>>>>>>> index 24a25d5..e54e59c 100644
>>>>>>> --- a/block.c
>>>>>>> +++ b/block.c
>>>>>>> @@ -29,6 +29,9 @@
>>>>>>>  #include "module.h"
>>>>>>>  #include "qemu-objects.h"
>>>>>>>
>>>>>>> +#include "qemu-timer.h"
>>>>>>> +#include "block/blk-queue.h"
>>>>>>> +
>>>>>>>  #ifdef CONFIG_BSD
>>>>>>>  #include <sys/types.h>
>>>>>>>  #include <sys/stat.h>
>>>>>>> @@ -58,6 +61,13 @@ static int bdrv_read_em(BlockDriverState *bs, 
>>>>>>> int64_t sector_num,
>>>>>>>  static int bdrv_write_em(BlockDriverState *bs, int64_t sector_num,
>>>>>>>                           const uint8_t *buf, int nb_sectors);
>>>>>>>
>>>>>>> +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);
>>>>>>>
>>>>>>> @@ -90,6 +100,20 @@ int is_windows_drive(const char *filename)
>>>>>>>  }
>>>>>>>  #endif
>>>>>>>
>>>>>>> +static int bdrv_io_limits_enable(BlockIOLimit *io_limits)
>>>>>>> +{
>>>>>>> +    if ((io_limits->bps[0] == 0)
>>>>>>> +         && (io_limits->bps[1] == 0)
>>>>>>> +         && (io_limits->bps[2] == 0)
>>>>>>> +         && (io_limits->iops[0] == 0)
>>>>>>> +         && (io_limits->iops[1] == 0)
>>>>>>> +         && (io_limits->iops[2] == 0)) {
>>>>>>> +        return 0;
>>>>>>> +    }
>>>>>>> +
>>>>>>> +    return 1;
>>>>>>> +}
>>>>>>> +
>>>>>>>  /* check if the path starts with "<protocol>:" */
>>>>>>>  static int path_has_protocol(const char *path)
>>>>>>>  {
>>>>>>> @@ -167,6 +191,28 @@ void path_combine(char *dest, int dest_size,
>>>>>>>      }
>>>>>>>  }
>>>>>>>
>>>>>>> +static void bdrv_block_timer(void *opaque)
>>>>>>> +{
>>>>>>> +    BlockDriverState *bs = opaque;
>>>>>>> +    BlockQueue *queue = bs->block_queue;
>>>>>>> +
>>>>>>> +    while (!QTAILQ_EMPTY(&queue->requests)) {
>>>>>>> +        BlockIORequest *request;
>>>>>>> +        int ret;
>>>>>>> +
>>>>>>> +        request = QTAILQ_FIRST(&queue->requests);
>>>>>>> +        QTAILQ_REMOVE(&queue->requests, request, entry);
>>>>>>> +
>>>>>>> +        ret = qemu_block_queue_handler(request);
>>>>>>> +        if (ret == 0) {
>>>>>>> +            QTAILQ_INSERT_HEAD(&queue->requests, request, entry);
>>>>>>> +            break;
>>>>>>> +        }
>>>>>>> +
>>>>>>> +        qemu_free(request);
>>>>>>> +    }
>>>>>>> +}
>>>>>>> +
>>>>>>>  void bdrv_register(BlockDriver *bdrv)
>>>>>>>  {
>>>>>>>      if (!bdrv->bdrv_aio_readv) {
>>>>>>> @@ -642,6 +688,15 @@ int bdrv_open(BlockDriverState *bs, const char 
>>>>>>> *filename, int flags,
>>>>>>>              bs->change_cb(bs->change_opaque, CHANGE_MEDIA);
>>>>>>>      }
>>>>>>>
>>>>>>> +    /* throttling disk I/O limits */
>>>>>>> +    if (bdrv_io_limits_enable(&bs->io_limits)) {
>>>>>>> +        bs->block_queue = qemu_new_block_queue();
>>>>>>> +        bs->block_timer = qemu_new_timer_ns(vm_clock, 
>>>>>>> bdrv_block_timer, bs);
>>>>>>> +
>>>>>>> +        bs->slice_start[0] = qemu_get_clock_ns(vm_clock);
>>>>>>> +        bs->slice_start[1] = qemu_get_clock_ns(vm_clock);
>>>>>>> +    }
>>>>>>> +
>>>>>>
>>>>>> It should be possible to tune the limits on the flight, please introduce
>>>>>> QMP commands for that.
>>>>> Yeah, I am working on this.
>>>>
>>>> It's worth mentioning that the I/O limits commands can use Supriya's
>>>> new block_set command for changing block device parameters at runtime.
>>>>  So I think the runtime limits changing can be a separate patch.
>>> Since I/O limits commands will depend on Supriya's block_set patch,
>>> when will her patch be merged into qemu.git?
>>
>> The block_set patch is on the mailing list with an ongoing discussion.
>>  Until agreement is reached it will not be merged - hard to tell when
>> exactly that will be, but hopefully over the next few days.
>>
>> You can always add temporary QMP/HMP commands in order to test setting
>> limits at runtime.  It should be easy to switch to a different QMP/HMP
>> command later, if necessary.
>
> Just to clarify: adding temporary QMP/HMP commands in your personal
> git repo can be useful for development and testing.  It will let you
> continue fleshing out things like block device hotplug.  Of course
> qemu.git can only merge commands that we intend to support for the
> future, so a final QMP/HMP interface needs to be written at some point
> but it does not stop you from making progress.
No matter. no pain, no gain. by adding temporary QMP/HMP commands, i
can learn about block device hotplug. I think that it is worth doing
it.

>
> Stefan
>



-- 
Regards,

Zhi Yong Wu