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

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Message-ID: <74385f9d-ed8d-8906-13e3-b3091dae7993@codethink.co.uk>
Date:   Tue, 11 Jul 2023 09:41:43 +0100
From:   Ben Dooks <ben.dooks@...ethink.co.uk>
To:     Eric Lin <eric.lin@...ive.com>,
        Conor Dooley <conor.dooley@...rochip.com>
Cc:     conor@...nel.org, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, palmer@...belt.com,
        paul.walmsley@...ive.com, aou@...s.berkeley.edu, maz@...nel.org,
        chenhuacai@...nel.org, baolu.lu@...ux.intel.com, will@...nel.org,
        kan.liang@...ux.intel.com, nnac123@...ux.ibm.com,
        pierre.gondois@....com, jgross@...e.com, chao.gao@...el.com,
        maobibo@...ngson.cn, linux-riscv@...ts.infradead.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        dslin1010@...il.com, Greentime Hu <greentime.hu@...ive.com>,
        Zong Li <zong.li@...ive.com>, Nick Hu <nick.hu@...ive.com>
Subject: Re: [PATCH 2/3] soc: sifive: Add SiFive private L2 cache PMU driver

On 20/06/2023 04:14, Eric Lin wrote:
> On Fri, Jun 16, 2023 at 6:13 PM Conor Dooley <conor.dooley@...rochip.com> wrote:
>>
>> On Fri, Jun 16, 2023 at 02:32:09PM +0800, Eric Lin wrote:
>>> From: Greentime Hu <greentime.hu@...ive.com>
>>>
>>> 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@...ive.com>
>>> Signed-off-by: Eric Lin <eric.lin@...ive.com>
>>> Reviewed-by: Zong Li <zong.li@...ive.com>
>>> Reviewed-by: Nick Hu <nick.hu@...ive.com>
>>> ---
>>>   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

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