linux-kernel - Re: [PATCH 0/2] arm64 SMMUv3 PMU driver with IORT support

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Message-ID: <5db10f59-e2dc-cb03-0950-58e14eac16e5@codeaurora.org>
Date:   Thu, 2 Nov 2017 16:38:27 -0400
From:   "Leeder, Neil" <nleeder@...eaurora.org>
To:     Yury Norov <ynorov@...iumnetworks.com>
Cc:     nleeder@...eaurora.org, Will Deacon <will.deacon@....com>,
        Mark Rutland <mark.rutland@....com>,
        Mark Langsdorf <mlangsdo@...hat.com>,
        Jon Masters <jcm@...hat.com>,
        Timur Tabi <timur@...eaurora.org>,
        linux-kernel@...r.kernel.org, Mark Brown <broonie@...nel.org>,
        Mark Salter <msalter@...hat.com>,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 0/2] arm64 SMMUv3 PMU driver with IORT support

Hi Yury,

On 10/31/2017 7:33 PM, Yury Norov wrote:
> Hi Neil,
> 
> On Fri, Aug 04, 2017 at 03:59:12PM -0400, Neil Leeder wrote:
>> This adds a driver for the SMMUv3 PMU into the perf framework.
>> It includes an IORT update to support PM Counter Groups.
>>
>> IORT has no mechanism for determining device names so PMUs
>> are named based on their physical address. 
>>
>> Tested on Qualcomm QDF2400. perf_fuzzer ran for 4+ hours
>> with no failures.
>>
>> Neil Leeder (2):
>>   acpi: arm64: add iort support for PMCG
>>   perf: add arm64 smmuv3 pmu driver
>>
>>  drivers/acpi/arm64/iort.c     |  54 +++
>>  drivers/perf/Kconfig          |   9 +
>>  drivers/perf/Makefile         |   1 +
>>  drivers/perf/arm_smmuv3_pmu.c | 823 ++++++++++++++++++++++++++++++++++++++++++
>>  include/acpi/actbl2.h         |   9 +-
>>  5 files changed, 895 insertions(+), 1 deletion(-)
>>  create mode 100644 drivers/perf/arm_smmuv3_pmu.c
> 
> I try to run your driver on ThunderX2, but perf list doesn't show new
> events, and example in description in patch 2 also doesn't work:
> yury@...1-25:~/linux$ tools/perf/perf stat -e smmu_0_ff88840/transaction,filter_enable=1, filter_span=1,filter_stream_id=0x42/ -a pwd
> event syntax error: '..ter_enable=1,'
>                                   \___ parser error
> Run 'perf list' for a list of valid events 
> 
>  Usage: perf stat [<options>] [<command>]
> 
>     -e, --event <event>   event selector. use 'perf list' to list available events
> 
> I run v4.14-rc7 kernel plus this series. The config is attached. I
> found that platform_match() never return 1 for arm-smmu-pmu and so
> the driver never probed.
> 
> Maybe it's my local configuration issue?

Thanks for testing this driver. As some of the review comments pointed out, there are
some changes needed which will be addressed in a future patchset. Notably the IORT
needs updating to handle the two base addresses. The current driver assumes the second
memory area is adjacent to the first, which may not be the case in all implementations.

In order to make the driver probe correctly, you'll need to update your ACPI tables
with entries for PMCG, node type 0x5. This ACPI information will include the two base
addresses. I've heard that the updated spec which will include the second memory
area will be available soon. At that point I will release another patchset for review.

Neil
-- 
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.