[PATCH v11 0/9] fix several inconsistencies with sysfs configuration in etmX

[Leo Yan]

On Tue, Sep 15, 2026 at 12:34:35PM +0100, Yeoreum Yun wrote:

> To resolve these inconsistencies, the configuration should be separated into:
> 
>   - active_config, which is applied configuration for the current session
>   - config, which stores the settings configured via sysfs.
> 
> and apply configuration from configfs after taking a mode.

I did the following tests on this series:

 1) Perf test on Orion6 board:

  # ./perf test coresight
  142: CoreSight synthesized callchain                                                                           : Ok
  143: CoreSight concurrent threads                                                                              : Ok
  144: CoreSight context switch thread attribution                                                               : Ok
  145: CoreSight deterministic workload decode                                                                   : Ok
  146: CoreSight raw dump stress                                                                                 : Ok
  147: Check Arm CoreSight trace data recording and synthesized samples                                          : FAILED!
  148: Check Arm CoreSight disassembly script completes without errors                                           : Ok

Test 147 has a known issue with per-thread mode. The failure was already
observed before this series.

 2) Strobe mode test:

  # echo 5000 > /sys/kernel/config/cs-syscfg/features/strobing/params/window/value

  # echo 0 > /sys/kernel/config/cs-syscfg/features/strobing/params/period/value
  # perf record -e cs_etm/autofdo,timestamp=0/u -m,128M  -- perf test -w brstack 3000000
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 36.301 MB perf.data ]

  # echo 1 > /sys/kernel/config/cs-syscfg/features/strobing/params/period/value
  # perf record -e cs_etm/autofdo,timestamp=0/u -m,128M  -- perf test -w brstack 3000000
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 18.361 MB perf.data ]

  # echo 2 > /sys/kernel/config/cs-syscfg/features/strobing/params/period/value
  # perf record -e cs_etm/autofdo,timestamp=0/u -m,128M  -- perf test -w brstack 3000000
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 12.246 MB perf.data ]

  # echo 3 > /sys/kernel/config/cs-syscfg/features/strobing/params/period/value
  # perf record -e cs_etm/autofdo,timestamp=0/u -m,128M  -- perf test -w brstack 3000000
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 9.197 MB perf.data ]

The captured trace sizes maintain the expected proportional relationship
with the period values.

 3) I verified the series on Juno-r2 baord with insmod and rmmod, and
    CPU PM, and did not see any regression.

Maybe it'd be good to send a new version addressing Mike's comments.
Based on the test results, you can add my test tags:

Tested-by: Leo Yan <leo.yan at arm.com>