[0/3] perf/arm-cmn: Multi-DTC improvements

Message

Robin Murphy Oct. 20, 2023, 5:51 p.m. UTC

On larger CMN configurations with multiple Debug & Trace Controllers,
we've so far ignored the notion of DTC domains, mostly since they were
not software-discoverable in the original CMN-600 design. However this
means that if the user wants to monitor lots of individual nodes across
the whole mesh, we end up multiplexing events which could otherwise
happily run in parallel if we allocated DTC counters per-domain. This
mini-series finally bites the bullet to do that.

As usual I've only been able to personally test that it doesn't regress
any behaviour on a single-DTC CMN-600, so it would be nice if anyone
with a multi-domain CMN-650/CMN-700 setup could confirm that patches 1+2
alone do not visibly change any behaviour, and then patch #3 on top
works as expected.

Thanks,
Robin.


Robin Murphy (3):
  perf/arm-cmn: Fix DTC domain detection
  perf/arm-cmn: Rework DTC counters (again)
  perf/arm-cmn: Enable per-DTC counter allocation

 drivers/perf/arm-cmn.c | 154 +++++++++++++++++++++++------------------
 1 file changed, 85 insertions(+), 69 deletions(-)

Comments

Will Deacon Oct. 23, 2023, 2:39 p.m. UTC | #1

On Fri, 20 Oct 2023 18:51:24 +0100, Robin Murphy wrote:
> On larger CMN configurations with multiple Debug & Trace Controllers,
> we've so far ignored the notion of DTC domains, mostly since they were
> not software-discoverable in the original CMN-600 design. However this
> means that if the user wants to monitor lots of individual nodes across
> the whole mesh, we end up multiplexing events which could otherwise
> happily run in parallel if we allocated DTC counters per-domain. This
> mini-series finally bites the bullet to do that.
> 
> [...]

Applied to will (for-next/perf), thanks!

[1/3] perf/arm-cmn: Fix DTC domain detection
      https://git.kernel.org/will/c/e3e73f511c49
[2/3] perf/arm-cmn: Rework DTC counters (again)
      https://git.kernel.org/will/c/7633ec2c262f
[3/3] perf/arm-cmn: Enable per-DTC counter allocation
      https://git.kernel.org/will/c/ab33c66fd8f1

Cheers,