From: Eugene Teo <eteo@redhat.com>
To: Helge Hafting <helge.hafting@aitel.hist.no>
Cc: "Böszörményi Zoltán" <zboszor@dunaweb.hu>, linux-kernel@vger.kernel.org
Subject: Re: How to determine whether a file was opened O_DIRECT?
Date: Mon, 09 Oct 2006 11:44:53 +0800 [thread overview]
Message-ID: <4529C5B5.4040804@redhat.com> (raw)
In-Reply-To: <44F400EA.5020506@aitel.hist.no>
Helge Hafting wrote:
> Böszörményi Zoltán wrote:
>> Hi,
>>
>> I would like to run some diagnostics on a database
>> process and I would like to know what flags it used
>> for opening its files. Is there any way to get this info?
>>
>> Thanks in advance,
>> Zoltán Böszörményi
>>
> 1. Look at the source code for the database - if you have it.
> 2. Run your database under strace, then search the voluminous
> output for "open" calls and look at the flags.
> 3. Patch your kernel to "printk" information whenever
> someone opens with O_DIRECT.
$ stap -x PID -e 'probe syscall.open { if (target() == pid()) log(argstr) }' \
| grep O_DIRECT
"/net", O_RDONLY|O_DIRECTORY|O_LARGEFILE|O_NONBLOCK
"/net", O_RDONLY|O_DIRECTORY|O_LARGEFILE|O_NONBLOCK
...
http://www.sourceware.org/systemtap
Eugene
--
eteo redhat.com ph: +65 6490 4142 http://www.kernel.org/~eugeneteo
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prev parent reply other threads:[~2006-10-09 8:25 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-08-29 8:03 How to determine whether a file was opened O_DIRECT? Böszörményi Zoltán
2006-08-29 8:55 ` Helge Hafting
2006-08-29 9:15 ` Böszörményi Zoltán
2006-10-09 3:44 ` Eugene Teo [this message]
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