Re: [PATCH v4 1/4] perf/core: Rework forwarding of {task|cpu}-clock events

[Ravi Bangoria]

Hi Pengfei,

On 20-Feb-24 2:11 PM, Pengfei Xu wrote:
> Hi Ravi Bangoria,
> 
> On 2023-05-04 at 16:30:00 +0530, Ravi Bangoria wrote:
>> Currently, PERF_TYPE_SOFTWARE is treated specially since task-clock and
>> cpu-clock events are interfaced through it but internally gets forwarded
>> to their own pmus.
>>
>> Rework this by overwriting event->attr.type in perf_swevent_init() which
>> will cause perf_init_event() to retry with updated type and event will
>> automatically get forwarded to right pmu. With the change, SW pmu no
>> longer needs to be treated specially and can be included in 'pmu_idr'
>> list.
>>
>> Suggested-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@xxxxxxx>
>> ---
>>  include/linux/perf_event.h | 10 +++++
>>  kernel/events/core.c       | 77 ++++++++++++++++++++------------------
>>  2 files changed, 51 insertions(+), 36 deletions(-)
> 
> Greeting!
> There is task hung in perf_tp_event_init in v6.8-rc4 in guest.

Thanks for the bug report. I'm able to reproduce it. Will try to spend
more time to rootcause it.

Thanks,
Ravi