Re: [PATCH] trace bio queueing trial only when it occurs

[Jens Axboe]

On Tue, Sep 08 2009, Wu Fengguang wrote:
> Minchan,
> 
> I tend to agree with the change, but somehow confused by blkparse(1):
> 
>         Q -- queued   This notes *intent* to queue i/o at the given location.  No real requests exists yet.
> 
> Li Zefan has been working on blktrace and he can tell more.

The documentation details the original implementation. I'm guessing the
need to move this trace hook is due to some user space tracking that
gets confused, because it cannot match the queue intent with a merge or
an insert.

I have no problems moving the trace call. If we had a matching bio_endio
trace, then I'd say moving it would lose information. But right now it
doesn't.

-- 
Jens Axboe

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