From: Arun Sharma <asharma@fb.com>
To: David Ahern <dsahern@gmail.com>
Cc: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: Using a new perf tool against an older kernel
Date: Thu, 23 Jun 2011 12:39:54 -0700 [thread overview]
Message-ID: <4E03968A.5010008@fb.com> (raw)
In-Reply-To: <4E034C2C.30509@gmail.com>
On 6/23/11 7:22 AM, David Ahern wrote:
> I have not seen issues like this using newer perf userspace against
> older kernels. For example, my laptop was running Fedora 14 (2.6.35) and
> now Fedora 15 (2.6.38.8) and I typically use latest perf builds (e.g.,
> testing patches).
I narrowed it down to PERF_SAMPLE_RAW:
perf record -ag -- sleep 1
is fine, but:
perf record -agR -- sleep 1
fails for me most of the time. The reason I needed to use the -R in the
first place is that "perf script" fails on older kernels with:
Samples do not contain timestamps.
With the newer perf, I don't get errors, but the timestamp field is
invalid. So I need to use the -R flag to get valid timestamps +
stacktraces out of "perf script".
-Arun
next prev parent reply other threads:[~2011-06-23 19:39 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-22 21:39 Using a new perf tool against an older kernel Arun Sharma
2011-06-23 14:22 ` David Ahern
2011-06-23 19:39 ` Arun Sharma [this message]
2011-06-23 20:02 ` David Ahern
2011-06-24 0:11 ` Frederic Weisbecker
2011-06-24 5:14 ` David Ahern
2011-06-24 0:11 ` Frederic Weisbecker
2011-06-24 0:43 ` Arun Sharma
2011-06-24 5:07 ` David Ahern
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