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<title>kernel/tools/perf/perf-iostat.sh, branch linux-6.2.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.</subtitle>
<id>https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-6.2.y</id>
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<updated>2021-04-20T11:40:20Z</updated>
<entry>
<title>perf stat: Enable iostat mode for x86 platforms</title>
<updated>2021-04-20T11:40:20Z</updated>
<author>
<name>Alexander Antonov</name>
<email>alexander.antonov@linux.intel.com</email>
</author>
<published>2021-04-19T09:41:46Z</published>
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This functionality is based on recently introduced sysfs attributes for
Intel® Xeon® Scalable processor family (code name Skylake-SP):

Commit bb42b3d39781d7fc ("perf/x86/intel/uncore: Expose an Uncore unit to IIO PMON mapping")

Mode is intended to provide four I/O performance metrics in MB per each
PCIe root port:

 - Inbound Read: I/O devices below root port read from the host memory
 - Inbound Write: I/O devices below root port write to the host memory
 - Outbound Read: CPU reads from I/O devices below root port
 - Outbound Write: CPU writes to I/O devices below root port

Each metric requiries only one uncore event which increments at every 4B
transfer in corresponding direction. The formulas to compute metrics
are generic:
    #EventCount * 4B / (1024 * 1024)

Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Signed-off-by: Alexander Antonov &lt;alexander.antonov@linux.intel.com&gt;
Cc: Alexander Shishkin &lt;alexander.shishkin@linux.intel.com&gt;
Cc: Alexey V Bayduraev &lt;alexey.v.bayduraev@linux.intel.com&gt;
Cc: Andi Kleen &lt;ak@linux.intel.com&gt;
Cc: Arnaldo Carvalho de Melo &lt;acme@kernel.org&gt;
Cc: Ian Rogers &lt;irogers@google.com&gt;
Cc: Ingo Molnar &lt;mingo@redhat.com&gt;
Cc: Jiri Olsa &lt;jolsa@redhat.com&gt;
Cc: Mark Rutland &lt;mark.rutland@arm.com&gt;
Cc: Peter Zijlstra &lt;peterz@infradead.org&gt;
Link: https://lore.kernel.org/r/20210419094147.15909-4-alexander.antonov@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo &lt;acme@redhat.com&gt;
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