[PATCH v2 0/2] perf alpha: Decode ProfileMe samples

[Matt Turner]

The Alpha kernel series "alpha/perf: add ProfileMe sampling" adds
ProfileMe sampling to the Alpha cpu PMU. Each ProfileMe sample carries
the profiled instruction's PMPC and its I_STAT and PCTR_CTL status as
PERF_SAMPLE_RAW data, which says whether the instruction retired,
whether it trapped and why, whether it was a mispredicted branch,
stalled before map, or was killed on a wrong path, and what PCTR1
counted while it was in flight:

  https://lore.kernel.org/r/20261030-alpha-profileme-v2-0-c702f1c65272@xxxxxxxxx

This series is the perf tool side. Patch 1 decodes the raw data in perf
report -D and perf script -D, as is done for AMD IBS. It copies the new
uapi header from the kernel series into tools/arch, so it should wait
until that header is merged. Patch 2 adds a script that sums the status
by symbol or by instruction, in the style of DCPI.

To try it, with the kernel series applied:

  perf record -R -e instructions:p -- ./workload
  tools/perf/python/alpha-profileme.py --pc

I tested this on an AlphaServer ES47 (EV7). Sampling a loop whose
branch tests random data reports that branch mispredicted in 21% of its
samples, and 0% with sorted data.

Signed-off-by: Matt Turner <mattst88@xxxxxxxxx>
---
Changes in v2:
- Patch 1: copy the raw data out of the sample and convert it from
  little endian, so that it decodes on strict-alignment and big-endian
  hosts.
- Patches 1 and 2: follow the new 28-byte struct alpha_profileme_sample
  from kernel v2.
- Link to v1: https://patch.msgid.link/20261028-perf-alpha-profileme-v1-0-f46c1938d001@xxxxxxxxx

To: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
To: Ingo Molnar <mingo@xxxxxxxxxx>
To: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
To: Namhyung Kim <namhyung@xxxxxxxxxx>
To: Mark Rutland <mark.rutland@xxxxxxx>
To: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
To: Jiri Olsa <jolsa@xxxxxxxxxx>
To: Ian Rogers <irogers@xxxxxxxxxx>
To: Adrian Hunter <adrian.hunter@xxxxxxxxx>
To: James Clark <james.clark@xxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Cc: linux-perf-users@xxxxxxxxxxxxxxx

---
Matt Turner (2):
      perf alpha: Decode ProfileMe raw samples
      perf python: Add alpha-profileme.py

 tools/arch/alpha/include/uapi/asm/perf_event.h |  31 +++++
 tools/perf/check-headers.sh                    |   1 +
 tools/perf/python/alpha-profileme.py           | 162 +++++++++++++++++++++++++
 tools/perf/util/Build                          |   1 +
 tools/perf/util/alpha-sample-raw.c             | 145 ++++++++++++++++++++++
 tools/perf/util/sample-raw.c                   |   2 +
 tools/perf/util/sample-raw.h                   |   2 +
 7 files changed, 344 insertions(+)
---
base-commit: 4626d370ae89b8af4d46a45372b269f926ec662d
change-id: 20261028-perf-alpha-profileme-8010299be323

Best regards,
--  
Matt Turner <mattst88@xxxxxxxxx>