Messages in this thread | | | Date | Mon, 10 Jul 2017 09:18:45 +0900 | From | Masami Hiramatsu <> | Subject | Re: tracing/kprobes: [Bug] Identical timestamps on two kprobes that are few instructions apart |
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Hello Arun,
On Fri, 7 Jul 2017 16:06:40 -0700 Arun Kalyanasundaram <arunkaly@google.com> wrote:
> Hi Steven, > > Thank you very much for your reply. I am using kernel - v4.12-rc3. > > I did something like this and see the issue: > # trace-cmd record -e kprobes:s1 -e kprobes:s2 -- taskset -c 0 my_program > # ./trace-cmd report -t --cpu 0 > > The issue is pretty intermittent and only happens when there are a lot > of samples, and so "my_program" generates a few hundred threads. Any > pointers on debugging this would be very helpful, or please let me > know if you want me to collect any log messages.
Ok, so this happens with ftrace+trace-cmd too. If you run it on x86-64, could you add "-C x86-tsc" and check still it happens? If not, I guess it happens when it adjusts timestamp.
Thank you,
-- Masami Hiramatsu <mhiramat@kernel.org>
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