Hi Suzuki, Mathieu,

On Tue, May 28, 2019 at 01:19:24PM +0800, Leo Yan wrote:

[...]

After I applied this patch set, I found all device names under
'/sys/bus/event_source/devices/cs_etm/sinks/' have been changed as
below on my DB410c board:
# ls /sys/bus/event_source/devices/cs_etm/sinks/
tmc_etf0  tmc_etr0  tpiu0

This leads to below command failure when open PMU device:
# perf record -e cs_etm/@826000.etr/ --per-thread uname
failed to set sink "826000.etr" on event cs_etm/@826000.etr/ with 2 (No such file or directory)

I must use below command so that perf can match string with the
device name under '/sys/bus/event_source/devices/cs_etm/sinks/':
# perf record -e cs_etm/@tmc_etr0/ --per-thread uname

Seems to me, this is an unexpected change and when I worked on the
patch set v2, IIRC that version still can use '826000.etr' to open PMU
device.

Please help confirm for this.  Thanks!

Finally, this is narrowed down to the patch 09/30 'coresight: Use
coresight device names for sinks in PMU attribute', so this is
delibrately to change to use new name format for perf command;
if so, maybe also update the documentation to reflect this change?

Thanks,
Leo Yan

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