On Wed, Nov 26, 2025 at 02:44:37PM +0000, Coresight ML wrote:
[...]
As far as I recall when this command line parameter was a bool then: perf -e cs_etm/timestamp/ <program> is sufficient to turn on timestamping.
Hmm... with the latest perf, we must assign value to `timestamp`, otherwise perf will report error:
# /mnt/build/perf record -e cs_etm/timestamp/ -C 0 -- taskset -c 0 ls event syntax error: 'cs_etm/timestamp/' ___ Bad event or PMU Unable to find PMU or event on a PMU of 'cs_etm' event syntax error: 'cs_etm/timestamp/' ___ no value assigned for term event syntax error: 'cs_etm/timestamp/' ___ no value assigned for term Run 'perf list' for a list of valid events
Apologize for this misinformation. When `timestamp` is bool, it does support the `-e cs_etm/timestamp/` format.
This is worth mentioning so users can correctly assess what happens for any existing scripts they might have.
Based on this then the same command must set the timestamp to 1 - which will have the same effect as before as we do not want to break existing behaviour.
Not sure if we need to record such info. Seems to me, it is weird that record a common behaviour for perf formats in this doc.
The perf error log would be sufficient for users to setup a proper format?
Thanks, Leo