From: "wcohen at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sourceware.org
Subject: [Bug translator/23866] dissonance between kernel tracepoint parametrization, lkm vs bpf
Date: Mon, 15 Jul 2019 20:00:00 -0000 [thread overview]
Message-ID: <bug-23866-6586-fHH2DjkWYm@http.sourceware.org/bugzilla/> (raw)
In-Reply-To: <bug-23866-6586@http.sourceware.org/bugzilla/>
https://sourceware.org/bugzilla/show_bug.cgi?id=23866
William Cohen <wcohen at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Attachment #11866|0 |1
is obsolete| |
Attachment #11901|0 |1
is obsolete| |
--- Comment #7 from William Cohen <wcohen at redhat dot com> ---
Created attachment 11907
--> https://sourceware.org/bugzilla/attachment.cgi?id=11907&action=edit
Revised version of the WIP bpf raw tracepoint support
The patch still needs some work:
-modify stapbpf/stapbpf.cxx to allow it to compile on machines that don't have
raw tracepoint support (for example rhel7).
-have clearer handling of things if using the older non-raw bpf tracepoints
-correct access of target struct field arguments (this issue can be seen in the
example below)
-cache tracequery results to speed up the process
$ ../install/bin/stap --bpf -e 'probe kernel.trace("sched_switch"){printf("%d
%p(%d) %p(%d)\n", $preempt, $prev, $prev->pid, $next, $next->pid)}' -T 0.01
0 0xffff8d78706b0000(7260) 0xffff8d78706b3380(7260)
0 0xffff8d78706b3380(29440) 0xffff8d78ba488000(29440)
0 0xffff8d78ba488000(11) 0xffff8d78bcd30000(11)
0 0xffff8d78bcd30000(7260) 0xffff8d78706b3380(7260)
1 0xffff8d78706b3380(1499) 0xffff8d7857d4b380(1499)
0 0xffff8d7857d4b380(6714) 0xffff8d7880628000(6714)
0 0xffff8d7880628000(748) 0xffff8d78ba48b380(748)
0 0xffff8d78ba48b380(29440) 0xffff8d78ba488000(29440)
0 0xffff8d78ba488000(489) 0xffff8d7876410000(489)
0 0xffff8d7876410000(7260) 0xffff8d78706b3380(7260)
0 0xffff8d78706b3380(1499) 0xffff8d7857d4b380(1499)
...
comparing to lkm version which has 0xffff8d78bcd30000(11) looks like getting
the fields for $prev wrong
$ ../install/bin/stap -e 'probe kernel.trace("sched_switch"){printf("%d %p(%d)
%p(%d)\n", $preempt, $prev, $prev->pid, $next, $next->pid)}' -T 0.01
0 0xffff8d78706b0000(11032) 0xffff8d787fb83380(11035)
0 0xffff8d787fb83380(11035) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d78ba488000(29440)
0 0xffff8d78ba488000(29440) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d78bcd30000(11)
0 0xffff8d78bcd30000(11) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d78bcd30000(11)
0 0xffff8d78bcd30000(11) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d78bcd30000(11)
0 0xffff8d78bcd30000(11) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d7857d48000(10951)
0 0xffff8d7857d48000(10951) 0xffff8d78bc6b8000(137)
1 0xffff8d78bc6b8000(137) 0xffff8d7857d48000(10951)
0 0xffff8d7857d48000(10951) 0xffff8d78bc6b8000(137)
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next prev parent reply other threads:[~2019-07-15 20:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-06 21:31 [Bug translator/23866] New: " fche at redhat dot com
2019-06-10 14:53 ` [Bug translator/23866] " fche at redhat dot com
2019-06-10 15:58 ` wcohen at redhat dot com
2019-06-12 14:22 ` wcohen at redhat dot com
2019-06-19 15:02 ` wcohen at redhat dot com
2019-06-25 13:40 ` wcohen at redhat dot com
2019-07-10 15:02 ` wcohen at redhat dot com
2019-07-15 20:00 ` wcohen at redhat dot com [this message]
2019-07-16 18:20 ` wcohen at redhat dot com
2019-07-18 14:43 ` wcohen at redhat dot com
2019-07-18 16:02 ` wcohen at redhat dot com
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