On Thu, Mar 21, 2019 at 11:05:57AM +0800, Leo Yan wrote:
[...]
- There is never any useful data in AUXTRACE sections of perf.data. When tracing with
--per-thread I observe that the size of the section grows significantly the longer I trace: ' ... CoreSight ETM Trace data: size xxx bytes' with xxx exceeding kBytes.
However, all I get is:
0xd60 [0x8]: event: 68 . . ... raw event: size 8 bytes . 0000: 44 00 00 00 00 00 08 00 D.......
0xd60 [0x8]: PERF_RECORD_FINISHED_ROUND
With --all-cpus, I always get ' ... CoreSight ETM Trace data: size 16 bytes' no matter how long the tracing session is.
FWIW, suggest you always to disable CPU idle state when use CoreSight, I remembered up before I captured empty trace data on Hikey if enable CPU idle. You could simply add 'nohlt' in kernel command for this.
Thanks, Leo Yan