Re: [PATCH] mmc: Provide tracepoints for request processing
From: Baolin Wang
Date: Mon Mar 28 2016 - 00:55:19 EST
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
>>> Most of these already exist as block layer trace points, why do we need
>>> 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