linux-kernel - RE: [PATCH 1/2] perf: Fujitsu: Add the Uncore MAC PMU driver

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Message-ID:
 <OS3PR01MB69039D08CF87FC69CDE6DD8FD4592@OS3PR01MB6903.jpnprd01.prod.outlook.com>
Date: Tue, 12 Nov 2024 07:49:23 +0000
From: "Yoshihiro Furudera (Fujitsu)" <fj5100bi@...itsu.com>
To: 'Krzysztof Kozlowski' <krzysztof.kozlowski@...aro.org>, Will Deacon
	<will@...nel.org>, Mark Rutland <mark.rutland@....com>, Jonathan Corbet
	<corbet@....net>, Catalin Marinas <catalin.marinas@....com>,
	"linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, Bjorn Andersson
	<quic_bjorande@...cinc.com>, Geert Uytterhoeven <geert+renesas@...der.be>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>, Konrad Dybcio
	<konradybcio@...nel.org>, Neil Armstrong <neil.armstrong@...aro.org>, Arnd
 Bergmann <arnd@...db.de>, Nícolas F. R. A. Prado
	<nfraprado@...labora.com>, Thomas Gleixner <tglx@...utronix.de>, Peter
 Zijlstra <peterz@...radead.org>, "linux-doc@...r.kernel.org"
	<linux-doc@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH 1/2] perf: Fujitsu: Add the Uncore MAC PMU driver

Hi, Krzysztof Kozlowski
Thanks for you review/comments.

> 
> On 08/11/2024 06:40, Yoshihiro Furudera wrote:
> > This adds a new dynamic PMU to the Perf Events framework to program
> > and control the Uncore MAC PMUs in Fujitsu chips.
> >
> > This driver was created with reference to drivers/perf/qcom_l3_pmu.c.
> >
> > This driver exports formatting and event information to sysfs so it
> > can be used by the perf user space tools with the syntaxes:
> >
> > perf stat -e mac_iod0_mac0_ch0/ea-mac/ ls perf stat -e
> > mac_iod0_mac0_ch0/event=0x80/ ls
> >
> > FUJITSU-MONAKA Specification URL:
> > https://github.com/fujitsu/FUJITSU-MONAKA
> >
> > Signed-off-by: Yoshihiro Furudera <fj5100bi@...itsu.com>
> > ---
> >  .../admin-guide/perf/fujitsu_mac_pmu.rst      |  20 +
> >  arch/arm64/configs/defconfig                  |   1 +
> 
> 
> defconfig goes via your SoC maintainer. Split the patch and Cc the SoC folks.

Understood.I'll do that and resubmit the patch.

> 
> Which ARCH is it, BTW?

This is supported by an ARM64-based processor called FUJITSU-MONAKA,
which is currently being developed by FUJITSU.

> 
> 
> >  drivers/perf/Kconfig                          |   9 +
> >  drivers/perf/Makefile                         |   1 +
> >  drivers/perf/fujitsu_mac_pmu.c                | 633
> ++++++++++++++++++
> >  include/linux/cpuhotplug.h                    |   1 +
> >  6 files changed, 665 insertions(+)
> >  create mode 100644 Documentation/admin-guide/perf/fujitsu_mac_pmu.rst
> >  create mode 100644 drivers/perf/fujitsu_mac_pmu.c
> >
> > diff --git a/Documentation/admin-guide/perf/fujitsu_mac_pmu.rst
> > b/Documentation/admin-guide/perf/fujitsu_mac_pmu.rst
> > new file mode 100644
> > index 000000000000..ddb3dcff3c61
> > --- /dev/null
> > +++ b/Documentation/admin-guide/perf/fujitsu_mac_pmu.rst
> > @@ -0,0 +1,20 @@
> >
> +==================================================
> ===================
> > +====== Fujitsu Uncore MAC Performance Monitoring Unit (PMU)
> >
> +==================================================
> ===================
> > +======
> > +
> > +This driver supports the Uncore MAC PMUs found in Fujitsu chips.
> > +Each MAC PMU on these chips is exposed as a uncore perf PMU with
> > +device name mac_iod<iod>_mac<mac>_ch<ch>.
> > +
> > +The driver provides a description of its available events and
> > +configuration options in sysfs, see
> /sys/bus/event_sources/devices/mac_iod<iod>_mac<mac>_ch<ch>/.
> > +Given that these are uncore PMUs the driver also exposes a "cpumask"
> > +sysfs attribute which contains a mask consisting of one CPU which
> > +will be used to handle all the PMU events.
> > +
> > +Examples for use with perf::
> > +
> > +  perf stat -e mac_iod0_mac0_ch0/ea-mac/ ls
> > +
> > +Given that these are uncore PMUs the driver does not support
> > +sampling, therefore "perf record" will not work. Per-task perf sessions are not
> supported.
> > diff --git a/arch/arm64/configs/defconfig
> > b/arch/arm64/configs/defconfig index 5fdbfea7a5b2..2ef412937228 100644
> > --- a/arch/arm64/configs/defconfig
> > +++ b/arch/arm64/configs/defconfig
> > @@ -1575,6 +1575,7 @@ CONFIG_ARM_CMN=m
> CONFIG_ARM_SMMU_V3_PMU=m
> > CONFIG_ARM_DSU_PMU=m  CONFIG_FSL_IMX8_DDR_PMU=m
> > +CONFIG_FUJITSU_MAC_PMU=y
> >  CONFIG_QCOM_L2_PMU=y
> >  CONFIG_QCOM_L3_PMU=y
> >  CONFIG_ARM_SPE_PMU=m
> > diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index
> > bab8ba64162f..4705c605e286 100644
> > --- a/drivers/perf/Kconfig
> > +++ b/drivers/perf/Kconfig
> > @@ -178,6 +178,15 @@ config FSL_IMX9_DDR_PMU
> >  	 can give information about memory throughput and other related
> >  	 events.
> >
> > +config FUJITSU_MAC_PMU
> > +	bool "Fujitsu Uncore MAC PMU"
> > +	depends on (ARM64 && ACPI) || (COMPILE_TEST && 64BIT)
> 
> Missing depends on specific ARCH.

This is because this driver supports the FUJITSU-MONAKA,
which is an ARM64 and ACPI-based processor.

> 
> Sorry, this looks like work for some out of tree arch support. I don't think we have
> any interest in taking it... unless it is part of bigger patchset/work? If so, then
> provide *lore* link to relevant patchset.

It is determined by the ACPI ID and does not depend on other patches.
(This ACPI ID is used by FUJITSU-MONAKA.)
The URLs of other patches related to FUJITSU-MONAKA are as follows:
https://lore.kernel.org/all/20241018015640.2924794-1-fj5100bi@fujitsu.com/
https://lore.kernel.org/all/20241024071553.3073864-1-fj5100bi@fujitsu.com/
https://lore.kernel.org/all/20241111064843.3003093-1-fj5100bi@fujitsu.com/
> 
> Best regards,
> Krzysztof
> 
> On 08/11/2024 12:03, Krzysztof Kozlowski wrote:
> > On 08/11/2024 06:40, Yoshihiro Furudera wrote:
> >> This adds a new dynamic PMU to the Perf Events framework to program
> >> and control the Uncore MAC PMUs in Fujitsu chips.
> >>
> >> This driver was created with reference to drivers/perf/qcom_l3_pmu.c.
> 
> This confused me...

This driver was created based on drivers/perf/qcom_l3_pmu.c.
The reason is that the processing done to Qualcomm's L3 cache PMU registers in
qcom_l3_pmu.c is similar to the processing done to the Uncore MAC/PCI PMU registers.
Specifically, the basic processing is the same as drivers/perf/qcom_l3_pmu.c,
but the variable names, function names, ACPI device ID, and some processing have
been modified to match FUJITSU-MONAKA's Uncore MAC PMU.

> 
> >>  CONFIG_ARM_SPE_PMU=m
> >> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index
> >> bab8ba64162f..4705c605e286 100644
> >> --- a/drivers/perf/Kconfig
> >> +++ b/drivers/perf/Kconfig
> >> @@ -178,6 +178,15 @@ config FSL_IMX9_DDR_PMU
> >>  	 can give information about memory throughput and other related
> >>  	 events.
> >>
> >> +config FUJITSU_MAC_PMU
> >> +	bool "Fujitsu Uncore MAC PMU"
> >> +	depends on (ARM64 && ACPI) || (COMPILE_TEST && 64BIT)
> >
> > Missing depends on specific ARCH.
> >
> > Sorry, this looks like work for some out of tree arch support. I don't
> > think we have any interest in taking it... unless it is part of bigger
> > patchset/work? If so, then provide *lore* link to relevant patchset.
> >
> 
> -ENOTENOUGHCOFFEE, I see now ACPI dependency so there will be no SoC
> folks for this, right?  Then anyway split work per subsystem and send
> defconfig to Soc maintainers.

Yes, we only use ACPI ID. 
I'll do that and resubmit the patch.

> Best regards,
> Krzysztof

Best Regards,
Yoshihiro Furudera