Re: [Qemu-devel] [PATCH v4 0/3] The intro for QEMU disk I/O limits

[Zhi Yong Wu]

On Tue, Aug 2, 2011 at 4:06 AM, Ryan Harper <address@hidden> wrote:
> * Zhi Yong Wu <address@hidden> [2011-08-01 01:30]:
>> The main goal of the patch is to effectively cap the disk I/O speed or 
>> counts of one single VM.It is only one draft, so it unavoidably has some 
>> drawbacks, if you catch them, please let me know.
>>
>> The patch will mainly introduce one block I/O throttling algorithm, one 
>> timer and one block queue for each I/O limits enabled drive.
>>
>> When a block request is coming in, the throttling algorithm will check if 
>> its I/O rate or counts exceed the limits; if yes, then it will enqueue to 
>> the block queue; The timer will handle the I/O requests in it.
>>
>> Some available features follow as below:
>> (1) global bps limit.
>>     -drive bps=xxx            in bytes/s
>> (2) only read bps limit
>>     -drive bps_rd=xxx         in bytes/s
>> (3) only write bps limit
>>     -drive bps_wr=xxx         in bytes/s
>> (4) global iops limit
>>     -drive iops=xxx           in ios/s
>> (5) only read iops limit
>>     -drive iops_rd=xxx        in ios/s
>> (6) only write iops limit
>>     -drive iops_wr=xxx        in ios/s
>> (7) the combination of some limits.
>>     -drive bps=xxx,iops=xxx
>>
>> Known Limitations:
>> (1) #1 can not coexist with #2, #3
>> (2) #4 can not coexist with #5, #6
>> (3) 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.
>>
>>
>> Zhi Yong Wu (3):
>>   v4: fix memory leaking based on ryan's feedback.
>
> It looks like the leak has been fixed, but I think we need to rework how
> the blk-queue is using the AIOPool.  I'll reply to that patch.
OK. Look forward to seeing it.
>
>
>
> --
> Ryan Harper
> Software Engineer; Linux Technology Center
> IBM Corp., Austin, Tx
> address@hidden
>



-- 
Regards,

Zhi Yong Wu