On Fri, Aug 12, 2011 at 6:35 AM, Zhi Yong Wu <zwu.kernel@xxxxxxxxx> wrote:
> On Tue, Aug 9, 2011 at 4:57 PM, Ram Pai <linuxram@xxxxxxxxxx> wrote:
>> On Tue, Aug 09, 2011 at 12:17:51PM +0800, Zhi Yong Wu 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@xxxxxxxxxxxxxxxxxx>
>>> ---
>>> block.c | 347 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++--
>>> block.h | 6 +-
>>> block_int.h | 30 +++++
>>> 3 files changed, 372 insertions(+), 11 deletions(-)
>>>
>>> diff --git a/block.c b/block.c
>>> index 24a25d5..8fd6643 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 +100,68 @@ 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;
>>> + bs->req_from_queue = false;
>>> +
>>> + if (bs->block_queue) {
>>> + qemu_block_queue_flush(bs->block_queue);
>>> + qemu_del_block_queue(bs->block_queue);
>>> + }
>>> +
>>> + if (bs->block_timer) {
>>> + qemu_del_timer(bs->block_timer);
>>> + qemu_free_timer(bs->block_timer);
>>> + }
>>> +
>>> + bs->slice_start[0] = 0;
>>> + bs->slice_start[1] = 0;
>>> +
>>> + bs->slice_end[0] = 0;
>>> + bs->slice_end[1] = 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->req_from_queue = false;
>>> +
>>> + 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] = qemu_get_clock_ns(vm_clock);
>>
>> a minor comment. better to keep the slice_start of the both the READ and WRITE
>> side the same.
>>
>> bs->slice_start[BLOCK_IO_LIMIT_WRITE] = bs->slice_start[BLOCK_IO_LIMIT_READ];
>>
>> saves a call to qemu_get_clock_ns().
>>
>>> +
>>> + bs->slice_end[BLOCK_IO_LIMIT_READ] =
>>> + qemu_get_clock_ns(vm_clock) + BLOCK_IO_SLICE_TIME;
>>
>> bs->slice_end[BLOCK_IO_LIMIT_READ] = bs->slice_start[BLOCK_IO_LIMIT_READ] +
>> BLOCK_IO_SLICE_TIME;
>>
>> saves one more call to qemu_get_clock_ns()
>>
>>> + bs->slice_end[BLOCK_IO_LIMIT_WRITE] =
>>> + qemu_get_clock_ns(vm_clock) + BLOCK_IO_SLICE_TIME;
>>
>>
>> bs->slice_end[BLOCK_IO_LIMIT_WRITE] = bs->slice_start[BLOCK_IO_LIMIT_WRITE] +
>> BLOCK_IO_SLICE_TIME;
>>
>> yet another call saving.
>>
>>
>>> +}
>>> +
>>> +bool bdrv_io_limits_enabled(BlockDriverState *bs)
>>> +{
>>> + BlockIOLimit *io_limits = &bs->io_limits;
>>> + if ((io_limits->bps[BLOCK_IO_LIMIT_READ] == 0)
>>> + && (io_limits->bps[BLOCK_IO_LIMIT_WRITE] == 0)
>>> + && (io_limits->bps[BLOCK_IO_LIMIT_TOTAL] == 0)
>>> + && (io_limits->iops[BLOCK_IO_LIMIT_READ] == 0)
>>> + && (io_limits->iops[BLOCK_IO_LIMIT_WRITE] == 0)
>>> + && (io_limits->iops[BLOCK_IO_LIMIT_TOTAL] == 0)) {
>>> + return false;
>>> + }
>>> +
>>> + return true;
>>> +}
>>
>> can be optimized to:
>>
>> 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]);
> I want to apply this, but it violate qemu coding styles.
Perhaps checkpatch.pl complains because of the (...) around the return
value. Try removing them.
Stefan
--
To unsubscribe from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
