i was attempting to use the latest version of userspace program, perf,
for my testing. however, i realize that this may not be appropriate as
perf should ideally be paired with the corresponding version of the
Linux kernel.
with newer kernels, we no longer need to specify specific cortex events
to retrieve status information. in contrast, with version 5.15, we had
to explicitly request the events we were interested in from the perf
list to obtain the desired status.
to achieve results consistent with the newer kernel, it’s not only
necessary to apply the patch mentioned in #2, but the perf tool also
needs to be updated. since we can specify events in version 5.15 to
retrieve status information, I think no additional changes are required
for 5.15.
** Changed in: linux-mtk (Ubuntu)
Status: In Progress => Won't Fix
** Changed in: linux-mtk (Ubuntu Jammy)
Status: In Progress => Won't Fix
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https://bugs.launchpad.net/bugs/2060063
Title:
PMU counters for Cortex-A78 not working correctly
Status in linux-mtk package in Ubuntu:
Won't Fix
Status in linux-mtk source package in Jammy:
Won't Fix
Bug description:
I am seeing an issue with the Cortex-A78 PMU counters on the
Genio1200-evk.
Linux perf reports <not counted> for Cortex-A78 PMUs when I run the following
commands:
taskset -c 7 perf stat -e cycles sleep 5
taskset -c 7 perf stat -r r11 sleep 5
Infact none of the standard PMU events on the Cortex-A78 work when
using the raw PMU event register values such as:
-e r08
-e r11
-e r13
:
...... etc.
I also see this behaviour when an application using libpfm4 OR
perf_event_open() API is pinned to one of the 4xCortex-A78 on the
board.
When I run the above perf commands and applications pinned to the
Cortex-A55 cores the PMU events get reported correctly.
Please let me know if you need more details.
Kind regards,
Umair
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