Hi Punit
On 15/11/2023 13:59, Punit Agrawal wrote:
Hi,
I am hitting some issues when capturing instruction trace using 'perf' on an Arm N2 based system.
After enabling ACPI support[0] for TRBE on top of v6.6, the kernel successfully probes all the ETE and TRBE devices. I see "ete" and "trbe" device folders (one per CPU) in /sys/bus/coresight/devices.
Do you see all trbe devices corresponding to the number of CPUs ?
When capturing trace using 'perf', I see the following error with no trace captured.
# perf record -e cs_etm//u <workload> failed to mmap with 12 (Cannot allocate memory)
That looks like a problem when you don't have a sink to capture the trace or there was an error in the allocation of memory.
The error goes away if a cpu is specified using '-C' option to 'perf record'
# perf record -e cs_etm//u -C 10 <workload> [...] [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.422 MB perf.data ]
That also looks suspicious as the size is too small. Does the perf report show any AUX records ?
Is this a known issue? Perhaps I am missing some required dependencies.
No, this is not.
Thanks, Punit
[0] https://lore.kernel.org/all/20230829135405.1159449-1-anshuman.khandual@arm.c...