Re: [PATCH 2/3] soc: sifive: Add SiFive private L2 cache PMU driver

[Ben Dooks]

On 20/06/2023 04:14, Eric Lin wrote:
> On Fri, Jun 16, 2023 at 6:13 PM Conor Dooley <conor.dooley@xxxxxxxxxxxxx> wrote:
> > On Fri, Jun 16, 2023 at 02:32:09PM +0800, Eric Lin wrote:
> > > From: Greentime Hu <greentime.hu@xxxxxxxxxx>
> > >
> > > This adds SiFive private L2 cache PMU driver. User
> > > can use perf tool to profile by event name and event id.
> > >
> > > Example:
> > > $ perf stat -C 0 -e /sifive_pl2_pmu/inner_acquire_block_btot/
> > >                  -e /sifive_pl2_pmu/inner_acquire_block_ntob/
> > >                  -e /sifive_pl2_pmu/inner_acquire_block_ntot/ ls
> > >
> > >   Performance counter stats for 'CPU(s) 0':
> > >
> > >                 300      sifive_pl2_pmu/inner_acquire_block_btot/
> > >               17801      sifive_pl2_pmu/inner_acquire_block_ntob/
> > >                5253      sifive_pl2_pmu/inner_acquire_block_ntot/
> > >
> > >         0.088917326 seconds time elapsed
> > >
> > > $ perf stat -C 0 -e /sifive_pl2_pmu/event=0x10001/
> > >                  -e /sifive_pl2_pmu/event=0x4001/
> > >                  -e /sifive_pl2_pmu/event=0x8001/ ls
> > >
> > >   Performance counter stats for 'CPU(s) 0':
> > >
> > >                 251      sifive_pl2_pmu/event=0x10001/
> > >                2620      sifive_pl2_pmu/event=0x4001/
> > >                 644      sifive_pl2_pmu/event=0x8001/
> > >
> > >         0.092827110 seconds time elapsed
> > >
> > > Signed-off-by: Greentime Hu <greentime.hu@xxxxxxxxxx>
> > > Signed-off-by: Eric Lin <eric.lin@xxxxxxxxxx>
> > > Reviewed-by: Zong Li <zong.li@xxxxxxxxxx>
> > > Reviewed-by: Nick Hu <nick.hu@xxxxxxxxxx>
> > > ---
> > >   drivers/soc/sifive/Kconfig            |   9 +
> > >   drivers/soc/sifive/Makefile           |   1 +
> > >   drivers/soc/sifive/sifive_pl2.h       |  20 +
> > >   drivers/soc/sifive/sifive_pl2_cache.c |  16 +
> > >   drivers/soc/sifive/sifive_pl2_pmu.c   | 669 ++++++++++++++++++++++++++
> >
> > Perf drivers should be in drivers/perf, no?
>
> Hi Conor,
>
> Yes, I see most of the drivers are in the drivers/perf.
>
> But I grep perf_pmu_register(), it seems not all the pmu drivers are
> in drivers/perf as below:
>
> arch/arm/mach-imx/mmdc.c:517:   ret =
> perf_pmu_register(&(pmu_mmdc->pmu), name, -1);
> arch/arm/mm/cache-l2x0-pmu.c:552:       ret =
> perf_pmu_register(l2x0_pmu, l2x0_name, -1);
> ...
> drivers/dma/idxd/perfmon.c:627: rc = perf_pmu_register(&idxd_pmu->pmu,
> idxd_pmu->name, -1);
> drivers/fpga/dfl-fme-perf.c:904:static int
> fme_perf_pmu_register(struct platform_device *pdev,
> drivers/fpga/dfl-fme-perf.c:929:        ret = perf_pmu_register(pmu, name, -1);
> ...
> drivers/gpu/drm/amd/amdgpu/amdgpu_pmu.c:549:    ret =
> perf_pmu_register(&pmu_entry->pmu, pmu_name, -1);
> drivers/gpu/drm/i915/i915_pmu.c:1190:   ret =
> perf_pmu_register(&pmu->base, pmu->name, -1);
> drivers/hwtracing/coresight/coresight-etm-perf.c:907:   ret =
> perf_pmu_register(&etm_pmu, CORESIGHT_ETM_PMU_NAME, -1);
> drivers/hwtracing/ptt/hisi_ptt.c:895:   ret =
> perf_pmu_register(&hisi_ptt->hisi_ptt_pmu, pmu_name, -1);
> drivers/iommu/intel/perfmon.c:570:      return
> perf_pmu_register(&iommu_pmu->pmu, iommu_pmu->pmu.name, -1);
> drivers/nvdimm/nd_perf.c:309:   rc = perf_pmu_register(&nd_pmu->pmu,
> nd_pmu->pmu.name, -1);
> ...
>
> I just wondering what kind of pmu drivers should be in drivers/perf
> and what kind of pmu drivers should not be in drivers/perf.
> Thanks.

Given the registers for the l2 cache controls and l2 pmu don't overlap
do we need the pmu and general cache drivers together?

--
Ben Dooks				http://www.codethink.co.uk/
Senior Engineer				Codethink - Providing Genius

https://www.codethink.co.uk/privacy.html