Re: [Qemu-devel] [PATCH v8 3/4] block: add block timer and throttling algorithm

[Zhi Yong Wu]

On Fri, Sep 9, 2011 at 10:44 PM, Marcelo Tosatti <address@hidden> wrote:
> On Thu, Sep 08, 2011 at 06:11:07PM +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.
>
> You can increase the length of the slice, if the request is larger than
> slice_time * bps_limit.
Yeah, but it is a challenge for how to increase it. Do you have some nice idea?

>
>>      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.
>
> Why?
This issue has not existed. I will remove it.
When drive bps=1000000, i did some testings on guest VM.
1.) bs=1024K
18+0 records in
18+0 records out
18874368 bytes (19 MB) copied, 26.6268 s, 709 kB/s
2.) bs=2048K
18+0 records in
18+0 records out
37748736 bytes (38 MB) copied, 46.5336 s, 811 kB/s

>
> There is lots of debugging leftovers in the patch.
sorry, i forgot to remove them.
>
>



-- 
Regards,

Zhi Yong Wu