* blktrace and dm devices?
@ 2008-10-30 13:56 Martin Peschke
2008-10-30 13:59 ` Jens Axboe
0 siblings, 1 reply; 2+ messages in thread
From: Martin Peschke @ 2008-10-30 13:56 UTC (permalink / raw)
To: linux-btrace
Hi,
I have noticed that I get C traces but no D traces for device mapper
devices. Is blktrace supposed to handle dm devices as well?
Thanks,
Martin
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: blktrace and dm devices?
2008-10-30 13:56 blktrace and dm devices? Martin Peschke
@ 2008-10-30 13:59 ` Jens Axboe
0 siblings, 0 replies; 2+ messages in thread
From: Jens Axboe @ 2008-10-30 13:59 UTC (permalink / raw)
To: linux-btrace
On Thu, Oct 30 2008, Martin Peschke wrote:
> Hi,
>
> I have noticed that I get C traces but no D traces for device mapper
> devices. Is blktrace supposed to handle dm devices as well?
The dispatch event is associated with request dispatching, which dm/md
does not do. You should get redirect events, telling you when the IO is
being redirected to the bottom device. Or split events.
--
Jens Axboe
^ permalink raw reply [flat|nested] 2+ messages in thread
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2008-10-30 13:56 blktrace and dm devices? Martin Peschke
2008-10-30 13:59 ` Jens Axboe
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