[dtrace-discuss] Tracing FDs

Michael Schuster
2011-01-05T05:59:54Z

On Wed, Jan 5, 2011 at 06:04, Shanya Jones <shanya_jones at yahoo.com>
wrote:
> Hi Casper:
>
> ? It is one of our application that is giving error.? We want to determine
if it the application that is using too many FDs or the system(Solaris 10)or DNS
that is using FDs.

perhaps you want to show the *exact* error you''re getting, and
describe the circumstances in some detail?

As Casper said, there''s no system-wide limit on file descriptors, so
if a specific process is running out of fds (that''s what I''m
assuming
is happening from what I''ve seen so far), then it''s that
process
that''s exceeding its limit - see "ulimit(1)" man-page.

> We want to find out which process is using how many FDs using dtrace at
give point and time - not lsof nor netstat, pfiles not snoop either, using none
of the system commands.

is this an academic exercise. or a real-world problem? if the latter,
use the tool for the problem not the tool of your fancy :-)

again. assuming it''s an open() system call that''s returning
the error
we''re discussing here in the abstract, using a probe looking something
like

pid$target:libc:open:return
/arg1 == -1 && errno == 24/
{
    ustack();
}

(but check the man pages and do some testing, I didn''t check all the
details)

will tell you a lot of where the specific error happens, but it may
not help pinpoint the code that''s "wasting" the fds, since
it''s going
to be the one that happens to trip over the limit, nothing more.

HTH
Michael
>
> Thanks,
> ? -Shanya
>
> --- On Thu, 12/30/10, Casper.Dik at Sun.COM <Casper.Dik at Sun.COM>
wrote:
>
>> From: Casper.Dik at Sun.COM <Casper.Dik at Sun.COM>
>> Subject: Re: [dtrace-discuss] Tracing FDs
>> To: "Shanya Jones" <shanya_jones at yahoo.com>
>> Cc: dtrace-discuss at opensolaris.org
>> Date: Thursday, December 30, 2010, 5:43 AM
>>
>> >Hi :
>> >
>> >? (Apology if this is too naive question.)
>> >? Our system is running out of FDs frequently.
>>
>> What is the exact symptom or error message?
>>
>> There is no limit on the global number of file descriptors
>> (assuming
>> you''re using Solaris)
>>
>> Casper
>>
>>
>
>
>
>
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>



--
regards/mit freundlichen Gr?ssen
Michael Schuster