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From: Blue Swirl <blauwirbel@gmail.com>
To: Stefan Hajnoczi <stefanha@gmail.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] trace: Trace SCSI request lifecycle
Date: Tue, 9 Nov 2010 17:47:24 +0000	[thread overview]
Message-ID: <AANLkTikKzKe+OOO4om3Z5JT4kLny1gSJQKTPCWvwxOhg@mail.gmail.com> (raw)
In-Reply-To: <AANLkTikuPFzM-hC=BzJMZ8BYPNr7aFDMK1cEUYiooWCg@mail.gmail.com>

On Mon, Nov 8, 2010 at 9:30 PM, Stefan Hajnoczi <stefanha@gmail.com> wrote:
> On Mon, Nov 8, 2010 at 7:18 PM, Blue Swirl <blauwirbel@gmail.com> wrote:
>> On Mon, Nov 8, 2010 at 9:44 AM, Stefan Hajnoczi
>> <stefanha@linux.vnet.ibm.com> wrote:
>>> This patch adds trace events for SCSI request allocation, freeing, CDB
>>> parsing, read, and write.  These trace events can be used to instrument
>>> the SCSI request lifecycle.
>>
>> How about converting also the DPRINTFs in hw/scsi-disk.c to tracepoints?
>
> Good idea.  I don't understand the SCSI emulation well enough to trace
> the rest, so I couldn't do much besides a mechanical conversion.

I also did only a mechanical conversion of Sparc32 devices earlier. I
thought about removing or merging some of them, but then I considered
that more tracepoints may be better to fewer. Is there a downside?

There's a difference in the viewpoints. DPRINTFs may have been
designed with debugging internal logic in mind. Alternatively we could
be interested in only tracing the external interfaces. I don't think
these views are in conflict since tracepoints are much more precise
than DPRINTFs.

  reply	other threads:[~2010-11-09 17:47 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-08  9:44 [Qemu-devel] [PATCH] trace: Trace SCSI request lifecycle Stefan Hajnoczi
2010-11-08 19:18 ` Blue Swirl
2010-11-08 21:30   ` Stefan Hajnoczi
2010-11-09 17:47     ` Blue Swirl [this message]
2010-11-10  9:22       ` Stefan Hajnoczi

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