> -----Original Message----- > From: Suzuki K Poulose <suzuki.poulose@xxxxxxx> > Sent: Monday, May 9, 2022 5:02 AM > To: Will Deacon <will@xxxxxxxxxx>; Besar Wicaksono > <bwicaksono@xxxxxxxxxx> > Cc: catalin.marinas@xxxxxxx; mark.rutland@xxxxxxx; linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux- > tegra@xxxxxxxxxxxxxxx; sudeep.holla@xxxxxxx; > thanu.rangarajan@xxxxxxx; Michael.Williams@xxxxxxx; Thierry Reding > <treding@xxxxxxxxxx>; Jonathan Hunter <jonathanh@xxxxxxxxxx>; Vikram > Sethi <vsethi@xxxxxxxxxx>; Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>; > Michael Williams (ATG) <Michael.Williams@xxxxxxx> > Subject: Re: [PATCH 0/2] perf: ARM CoreSight PMU support > > External email: Use caution opening links or attachments > > > Cc: Mike Williams, Mathieu Poirier > > On 09/05/2022 10:28, Will Deacon wrote: > > On Sun, May 08, 2022 at 07:28:08PM -0500, Besar Wicaksono wrote: > >> Add driver support for ARM CoreSight PMU device and event attributes > for NVIDIA > >> implementation. The code is based on ARM Coresight PMU architecture > and ACPI ARM > >> Performance Monitoring Unit table (APMT) specification below: > >> * ARM Coresight PMU: > >> https://developer.arm.com/documentation/ihi0091/latest > >> * APMT: https://developer.arm.com/documentation/den0117/latest > >> > >> Notes: > >> * There is a concern on the naming of the PMU device. > >> Currently the driver is probing "arm-coresight-pmu" device, however > the APMT > >> spec supports different kinds of CoreSight PMU based implementation. > So it is > >> open for discussion if the name can stay or a "generic" name is required. > >> Please see the following thread: > >> http://lists.infradead.org/pipermail/linux-arm-kernel/2022- > May/740485.html > >> > >> Besar Wicaksono (2): > >> perf: coresight_pmu: Add support for ARM CoreSight PMU driver > >> perf: coresight_pmu: Add support for NVIDIA SCF and MCF attribute > >> > >> arch/arm64/configs/defconfig | 1 + > >> drivers/perf/Kconfig | 2 + > >> drivers/perf/Makefile | 1 + > >> drivers/perf/coresight_pmu/Kconfig | 10 + > >> drivers/perf/coresight_pmu/Makefile | 7 + > >> .../perf/coresight_pmu/arm_coresight_pmu.c | 1317 > +++++++++++++++++ > >> .../perf/coresight_pmu/arm_coresight_pmu.h | 147 ++ > >> .../coresight_pmu/arm_coresight_pmu_nvidia.c | 300 ++++ > >> .../coresight_pmu/arm_coresight_pmu_nvidia.h | 17 + > >> 9 files changed, 1802 insertions(+) > > > > How does this interact with all the stuff we have under > > drivers/hwtracing/coresight/? > > Absolutely zero, except for the name. The standard > is named "CoreSight PMU" which is a bit unfortunate, > given the only link, AFAIU, with the "CoreSight" architecture > is the Lock Access Register(LAR). For reference, the > drivers/hwtracing/coresight/ is purely "CoreSight" self-hosted > tracing and the PMU is called "cs_etm" (expands to coresight etm). > Otherwise the standard doesn't have anything to do with what > exists already in the kernel. Yes, there is no correlation or interaction with existing driver for ETM/STM tracing. It might share same authentication interface (NIDEN, DBGEN, SPIDEN, SPNIDEN) for external debug. But these are not used in the driver. > > That said, I am concerned that the "coresight_pmu" is easily confused > with what exists today. Given that this is more of a "PMU" standard > for the IPs in the Arm world, it would be better to name it as such > avoiding any confusion with the existing PMUs. > > One potential recommendation for the name is, "Arm PMU" (The ACPI table > is named Arm PMU Table). But then that could be clashing with the > armv8_pmu :-(. > > Some of the other options are : > > "Arm Generic PMU" > "Arm Uncore PMU" > "Arm PMU" As far as I understand, the APMT does not cover PMU in Arm PE. I think "Arm Uncore PMU" would fit. Regards, Besar > > Suzuki > > > > > Will
