linux-kernel - Re: [PATCH v7 7/9] perf: arm64: Add test for userspace counter access on heterogeneous systems

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Date:   Thu, 13 May 2021 07:37:24 -0500
From:   Rob Herring <robh@...nel.org>
To:     "nakamura.shun@...itsu.com" <nakamura.shun@...itsu.com>
Cc:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        "honnappa.nagarahalli@....com" <honnappa.nagarahalli@....com>,
        "Zachary.Leaf@....com" <Zachary.Leaf@....com>,
        Raphael Gault <raphael.gault@....com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Itaru Kitayama <itaru.kitayama@...il.com>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v7 7/9] perf: arm64: Add test for userspace counter access
 on heterogeneous systems

On Thu, May 13, 2021 at 4:06 AM nakamura.shun@...itsu.com
<nakamura.shun@...itsu.com> wrote:
>
> Hi Rob
>
> > Userspace counter access only works on heterogeneous systems with some
> > restrictions. The userspace process must be pinned to a homogeneous
> > subset of CPUs and must open the corresponding PMU for those CPUs. This
> > commit adds a test implementing these requirements.
>
> Are you planning to change x86 tests (tools/perf/arch/x86/tests/rdpmc.c)
> to use libperf as well?

The test can be removed as the libperf unit tests have an equivalent
test. I had a patch doing this, but there were objections removing it
until 'perf test' can run the libperf tests.

Rob