10 Mar
2025
10 Mar
'25
6:03 p.m.
On Mon, Mar 10, 2025 at 04:37:44PM +0000, Suzuki Kuruppassery Poulose wrote:
[...]
How about we dynamically set the default flag in the Perf tool?
- If users set explictly the 'update_buf_on_pause' flag, then the setting will be respected.
- If users don't set the flag, perf tool detects it is TRBE sinks, then it can set 'update_buf_on_pause' flag as false.
Not really possible. There could be systems with mixed sinks. e.g. TRBE for some CPU and ETR for others (say due to a non-functioning TRBE).
- If users don't set the flag, perf tool detects it is ETF/ETB/ETR sinks, it sets the flag as true.
And in the cases above, perf event cannot run on all the CPUs, because some sinks don't support it.
Why do we need a flag, when the effect is not user (read, perf decoder) visible and at the same time improves some scenarios (read non-TRBE cases) ?
Indeed in this case the flag is redundant.
I would say, let the driver always update on pause, depending on the sink.
It is fine for me. I will move towards this direction.
Thanks, Leo