On Thu, Jun 23, 2011 at 02:02:15PM -0600, David Ahern wrote:

On 06/23/2011 01:39 PM, Arun Sharma wrote:

quoted

On 6/23/11 7:22 AM, David Ahern wrote:

quoted

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".

That should have been fixed.

And -T on record gets the timestamps.

David

Right, it would be nice to suggest that from perf script when timestamps
are not recorded.