Question: SMMUv3 PMU event aliasing

Leo Yan leo.yan at linaro.org
Mon Nov 8 17:48:43 PST 2021


Hi John,

On Mon, Nov 08, 2021 at 12:41:33PM +0000, John Garry wrote:

[...]

> > Could you share current status (or plan) for upstreaming SMMUv3 PMU
> > event alias?  Or if there have any block issue to prevent merging the
> > changes in the mainline kernel?
> 
> This feature should be supported in the SMMUv3 PMU kernel driver and perf
> tool.
> 
> However it relies on the SMMU PMU identifier sysfs file to work. This relies
> on SMMU_PMCG_IIDR being set, which is introduced latest spec, which not much
> HW will support yet - see commit 2c255223362e. In theory we don't need that
> for the fixed, non-IMPDEF events, but I did not complicate perf tool with
> that mixed support.
> 
> That's the reason for which I paused smmuv3-pmcg.json upstream in [3]. I
> will revive that for new gen HW when concrete IMPDEF events known and
> shared.

Thanks for info.  When send out the new patch, you are welcome to Cc
to me, I am glad to give a test on D06 board (its IIDR is zero, so
I need to tweak a bit in driver for IIDR :)).

Thanks,
Leo



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