Re: [PATCH] mmc: Provide tracepoints for request processing

[Baolin Wang]

On 25 March 2016 at 22:07, Jens Axboe <axboe@xxxxxx> wrote:
> On 03/25/2016 01:32 AM, Baolin Wang wrote:
>>
>> On 24 March 2016 at 22:08, Jens Axboe <axboe@xxxxxx> wrote:
>>>
>>> On 03/24/2016 05:54 AM, Baolin Wang wrote:
>>>>
>>>>
>>>> This patch provides some tracepoints for the lifecycle of a request from
>>>> fetching to completion to help with performance analysis of MMC
>>>> subsystem.
>>>
>>>
>>>
>>> Most of these already exist as block layer trace points, why do we need
>>> mmc
>>> specific ones?
>>
>>
>> Currently the MMC core does not have any tracepoints for use with
>> ftrace. These are very useful as they provide a very low overhead
>> runtime controllable way of getting diagnostics from the system which
>> is capable of recording a great deal of information without impacting
>> system performance. We have tracepoints in the block layer so we can
>> do some trace of MMC but none in MMC itself so adding some where
>> appropriate would help people follow the activity of subsystem.
>
>
> But more than half of the trace points you added, those are DIRECTLY related
> to the block event. So what you are saying makes little sense. I see you
> resend it with the same trace points, I'll comment on that mail.

OK. I'll address your comments on that new mail. Thanks.

>
> --
> Jens Axboe
>



-- 
Baolin.wang
Best Regards