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0ffca606e9
On graniterapids the cache home agent (CHA) and memory controller
(IMC) PMUs all have their cpumask set to per-socket information. In
order for per NUMA node aggregation to work correctly the PMUs cpumask
needs to be set to CPUs for the relevant sub-NUMA grouping.
For example, on a 2 socket graniterapids machine with sub NUMA
clustering of 3, for uncore_cha and uncore_imc PMUs the cpumask is
"0,120" leading to aggregation only on NUMA nodes 0 and 3:
```
$ perf stat --per-node -e 'UNC_CHA_CLOCKTICKS,UNC_M_CLOCKTICKS' -a sleep 1
Performance counter stats for 'system wide':
N0 1 277,835,681,344 UNC_CHA_CLOCKTICKS
N0 1 19,242,894,228 UNC_M_CLOCKTICKS
N3 1 277,803,448,124 UNC_CHA_CLOCKTICKS
N3 1 19,240,741,498 UNC_M_CLOCKTICKS
1.002113847 seconds time elapsed
```
By updating the PMUs cpumasks to "0,120", "40,160" and "80,200" then
the correctly 6 NUMA node aggregations are achieved:
```
$ perf stat --per-node -e 'UNC_CHA_CLOCKTICKS,UNC_M_CLOCKTICKS' -a sleep 1
Performance counter stats for 'system wide':
N0 1 92,748,667,796 UNC_CHA_CLOCKTICKS
N0 0 6,424,021,142 UNC_M_CLOCKTICKS
N1 0 92,753,504,424 UNC_CHA_CLOCKTICKS
N1 1 6,424,308,338 UNC_M_CLOCKTICKS
N2 0 92,751,170,084 UNC_CHA_CLOCKTICKS
N2 0 6,424,227,402 UNC_M_CLOCKTICKS
N3 1 92,745,944,144 UNC_CHA_CLOCKTICKS
N3 0 6,423,752,086 UNC_M_CLOCKTICKS
N4 0 92,725,793,788 UNC_CHA_CLOCKTICKS
N4 1 6,422,393,266 UNC_M_CLOCKTICKS
N5 0 92,717,504,388 UNC_CHA_CLOCKTICKS
N5 0 6,421,842,618 UNC_M_CLOCKTICKS
1.003406645 seconds time elapsed
```
In general, having the perf tool adjust cpumasks isn't desirable as
ideally the PMU driver would be advertising the correct cpumask.
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Tested-by: Weilin Wang <weilin.wang@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250515181417.491401-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.