From: Steven Rostedt <rostedt@goodmis.org>
To: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Cc: linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH 5/5] [WIP] trace-cmd: Add new subcomand "trace-cmd perf"
Date: Thu, 18 Feb 2021 22:53:14 -0500 [thread overview]
Message-ID: <20210218225314.76166422@oasis.local.home> (raw)
In-Reply-To: <20210218210352.61470b93@oasis.local.home>
On Thu, 18 Feb 2021 21:03:52 -0500
Steven Rostedt <rostedt@goodmis.org> wrote:
> Hence, we can use x86-tsc as the clock for both the host and guest, and
> then using perf find out how to convert that to what the 'local' clock
> would produce. At least the multiplier and the shfit.
I just tried this out:
http://rostedt.org/private/perf-trace.c
Where I did:
# trace-cmd record -M 1 -C local -e irq -e sched taskset -c 0 ./perf-trace
time_shift=31
time_mult=633046315
time_offset=-125757047487632
# trace-cmd report |grep print taskset-34857 [000] 125742.260276: print: tracing_mark_write: [426606557411358] [125757.283123254] - <idle>-0 [0] softirq_raise: vec=9 [action=RCU]
taskset-34857 [000] 125742.260283: print: tracing_mark_write: [426606557431758] [125757.283129268] - <idle>-0 [0] softirq_entry: vec=9 [action=RCU]
taskset-34857 [000] 125742.260289: print: tracing_mark_write: [426606557580560] [125757.283173133] - <idle>-0 [0] softirq_exit: vec=9 [action=RCU]
taskset-34857 [000] 125742.260295: print: tracing_mark_write: [426606560784758] [125757.284117683] - <idle>-0 [0] softirq_raise: vec=7 [action=SCHED]
The time offset is slightly different, but we don't care. We only want
to convert the cycles into nanoseconds, and this appears to do the job!
-- Steve
next prev parent reply other threads:[~2021-02-19 3:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-03 6:02 [PATCH 0/5] Initial trace-cmd perf support Tzvetomir Stoyanov (VMware)
2020-12-03 6:02 ` [PATCH 1/5] trace-cmd: Internal refactoring of pid address map logic Tzvetomir Stoyanov (VMware)
2020-12-03 6:02 ` [PATCH 2/5] trace-cmd: Make read_file_string() non static Tzvetomir Stoyanov (VMware)
2020-12-03 6:02 ` [PATCH 3/5] trace-cmd: New internal APIs for reading ELF header Tzvetomir Stoyanov (VMware)
2020-12-03 6:02 ` [PATCH 4/5] trace-cmd: Add a new option in trace.dat file for the address to function name mapping Tzvetomir Stoyanov (VMware)
2020-12-03 6:02 ` [PATCH 5/5] [WIP] trace-cmd: Add new subcomand "trace-cmd perf" Tzvetomir Stoyanov (VMware)
2021-02-19 2:03 ` Steven Rostedt
2021-02-19 3:53 ` Steven Rostedt [this message]
2021-02-19 17:51 ` Dario Faggioli
2021-02-19 7:16 ` Tzvetomir Stoyanov
2021-02-19 14:36 ` Steven Rostedt
2021-02-19 17:56 ` Tzvetomir Stoyanov
2021-02-19 19:11 ` Steven Rostedt
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