Re: Using a new perf tool against an older kernel
From: Arun Sharma
Date: Thu Jun 23 2011 - 15:39:10 EST
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
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