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Fwd: Systemtap support for disk i/o per pid
- From: "James Dickens" <jamesd dot wi at gmail dot com>
- To: systemtap at sourceware dot org
- Date: Sun, 28 May 2006 14:10:31 -0500
- Subject: Fwd: Systemtap support for disk i/o per pid
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---------- Forwarded message ----------
From: James Dickens <jamesd.wi@gmail.com>
Date: May 28, 2006 2:08 PM
Subject: Re: Systemtap support for disk i/o per pid
To: Li Guanglei <guanglei@cn.ibm.com>
Cc: R Blundell <rickb@rapidvps.com>, systemtap@sourceware.org
On 5/27/06, Li Guanglei <guanglei@cn.ibm.com> wrote:
R Blundell ??:
> Hello, this is my first post to the mailing list. Does or will systemtap
> support "per pid" disk i/o accounting/details? I could not find any
> mention of this specifically on the website, papers, etc.
>
> Thank you
> Rick
Currently systemtap could be able to trace the io scheduler activities
and scsi activities. You could use "man lket" to get more details.
Some event hooks in these two categories could be filtered by pid. But
you can just trace all of them and later filter by pid in user space.
it would be simpler in most cases to probe syscalls that are easily
trackable to pid's though this won't give a totally accurate of IO
because of caching, but it is the easiest, and safest. When you go to
lower level kernel interfaces it becomes difficult to attiribute
actions with the pid that caused them.
James Dickens
uadmin.blogspot.com