perf docs: Update SPE doc to include default instructions group

The instructions group is now generated by default so update the doc to
reflect this. Also explain the period/downsampling mechanism in more
detail.

Signed-off-by: James Clark <james.clark@linaro.org>
Tested-by: Leo Yan <leo.yan@arm.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ben Gainey <Ben.Gainey@arm.com>
Cc: George Wort <George.Wort@arm.com>
Cc: Graham Woodward <Graham.Woodward@arm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Leo Yan <leo.yan@linux.dev>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Williams <Michael.Williams@arm.com>
Cc: Mike Leach <mike.leach@linaro.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/Documentation/perf-arm-spe.txt b/tools/perf/Documentation/perf-arm-spe.txt
index 37afade4f1b2c2ddb33e0be7e66fbedfb8c25eff..cda8dd47fc4dc9f6cb7d6459eeab18a1c66e1168 100644 (file)
--- a/tools/perf/Documentation/perf-arm-spe.txt
+++ b/tools/perf/Documentation/perf-arm-spe.txt
@@ -191,14 +191,20 @@ groups:
   36 branch
   0 remote-access
   900 memory
+  1800 instructions
 
 The arm_spe// and dummy:u events are implementation details and are expected to be empty.
 
-To get a full list of unique samples that are not sorted into groups, set the itrace option to
-generate 'instruction' samples. The period option is also taken into account, so set it to 1
-instruction unless you want to further downsample the already sampled SPE data:
+The instructions group contains the full list of unique samples that are not
+sorted into other groups. To generate only this group use --itrace=i1i.
 
-  perf report --itrace=i1i
+1i (1 instruction interval) signifies no further downsampling. Rather than an
+instruction interval, this generates a sample every n SPE samples. For example
+to generate the default set of events for every 100 SPE samples:
+
+  perf report --itrace==bxofmtMai100i
+
+Other period types, for example nanoseconds (ns) are not currently supported.
 
 Memory access details are also stored on the samples and this can be viewed with: