From: "dsmith at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug uprobes/17623] Sometimes probes fail to fire events when running against a multi-threaded application
Date: Fri, 21 Nov 2014 14:45:00 -0000 [thread overview]
Message-ID: <bug-17623-6586-eQnPnZ10J2@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-17623-6586@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=17623
--- Comment #7 from David Smith <dsmith at redhat dot com> ---
(In reply to Peter Allin from comment #6)
> (In reply to David Smith from comment #5)
> > On my F20 vm (3.16.3-200.fc20.x86_64), your test program and script worked
> > fine (even at WAIT_US 1). What kernel are you running?
>
> That sounds promising :-) I am running a kernel supplied by the Ubuntu
> project, they call it "3.13.0-24-generic #47-Ubuntu". I am working remotely
> today, and won't risk loosing access to the server by messing a kernel
> upgrade up (got to get that remote power switch configured..), but I'll
> defintely try upgrading it on monday.
>
> > When you finally stopped systemtap, did it report any skipped probes?
>
> No I haven't seen any such reports. I stop it either by ctrl-c or by running
> it under the "timeout" command. Could these ways of stopping it inhibit
> messages about skipped probes?
The skipped probes message would have come out at the end after either using
ctrl-c or using the timeout command.
> > Depending on what you get with test2.stp, can I ask you to try with HEAD
> > systemtap and see what you get?
>
> The behavior is consistent with my version of the script. If I run the
> testprogram with the -c option of stap, I gets equals counts. When I run the
> test program in the background only "func1" is counted. (I don't know if
> this could give any hints, if I switch the order of the probes in the .stp
> file, it is "func2" that works).
>
> Given this result, whould it make sense to try out the HEAD systemtap?
It might if you have the time. It will provide another data point to whether
this is a kernel issue or a systemtap issue.
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next prev parent reply other threads:[~2014-11-21 14:45 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-19 13:51 [Bug uprobes/17623] New: " peter at peca dot dk
2014-11-19 13:51 ` [Bug uprobes/17623] " peter at peca dot dk
2014-11-19 14:39 ` fche at redhat dot com
2014-11-20 7:49 ` peter at peca dot dk
2014-11-20 7:54 ` peter at peca dot dk
2014-11-20 17:04 ` dsmith at redhat dot com
2014-11-21 7:31 ` peter at peca dot dk
2014-11-21 14:45 ` dsmith at redhat dot com [this message]
2014-11-23 7:40 ` peter at peca dot dk
2014-11-23 7:53 ` peter at peca dot dk
2014-11-23 16:49 ` peter at peca dot dk
2014-11-24 15:17 ` dsmith at redhat dot com
2014-11-25 10:24 ` peter at peca dot dk
2021-05-03 22:34 ` fche at redhat dot com
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