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Ian Rogers 064647d61c perf python: Add evlist compute_metric
Add a compute_metric function that computes a metric double value for a
given evlist, metric name, CPU and thread. For example:
```
>>> import perf
>>> x = perf.parse_metrics("TopdownL1")
>>> x.open()
>>> x.enable()
>>> x.disable()
>>> x.metrics()
['tma_bad_speculation', 'tma_frontend_bound', 'tma_backend_bound', 'tma_retiring']
>>> x.compute_metric('tma_bad_speculation', 0, -1)
0.08605342847131037
```

Committer notes:

Initialize thread_idx and cpu_idx to zero as albeit them not possibly
coming out unitialized from the loop as mexp would be not NULL only if
they were initialized, some older compilers don't notice that and error
with:

    GEN     /tmp/build/perf/python/perf.cpython-36m-x86_64-linux-gnu.so
  /git/perf-6.17.0-rc3/tools/perf/util/python.c: In function ‘pyrf_evlist__compute_metric’:
  /git/perf-6.17.0-rc3/tools/perf/util/python.c:1363:3: error: ‘thread_idx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
     evsel__read_counter(metric_events[i], cpu_idx, thread_idx);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /git/perf-6.17.0-rc3/tools/perf/util/python.c:1389:41: note: ‘thread_idx’ was declared here
    int ret, cpu = 0, cpu_idx, thread = 0, thread_idx;
                                           ^~~~~~~~~~
  /git/perf-6.17.0-rc3/tools/perf/util/python.c:1363:3: error: ‘cpu_idx’ may be used uninitialized in this function [-Werror=maybe-uninitialized]
     evsel__read_counter(metric_events[i], cpu_idx, thread_idx);
     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  /git/perf-6.17.0-rc3/tools/perf/util/python.c:1389:20: note: ‘cpu_idx’ was declared here
    int ret, cpu = 0, cpu_idx, thread = 0, thread_idx;
                      ^~~~~~~
  /git/perf-6.17.0-rc3/tools/perf/util/python.c: At top level:
  cc1: error: unrecognized command line option ‘-Wno-cast-function-type’ [-Werror]
  cc1: all warnings being treated as errors
  error: command 'gcc' failed with exit status 1
  cp: cannot stat '/tmp/build/perf/python_ext_build/lib/perf*.so': No such file or directory

Reviewed-by: Howard Chu <howardchu95@gmail.com>
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Chun-Tse Shao <ctshao@google.com>
Cc: Collin Funk <collin.funk1@gmail.com>
Cc: Dr. David Alan Gilbert <linux@treblig.org>
Cc: Gautam Menghani <gautam@linux.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Falcon <thomas.falcon@intel.com>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Cc: Tiezhu Yang <yangtiezhu@loongson.cn>
Cc: Weilin Wang <weilin.wang@intel.com>
Cc: Xu Yang <xu.yang_2@nxp.com>
Link: https://lore.kernel.org/r/20250819013941.209033-9-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2025-09-03 12:34:54 -03:00
arch - Fix the GDS mitigation detection on some machines after the recent attack 2025-08-24 09:52:28 -04:00
block block: avoid cpu_hotplug_lock depedency on freeze_lock 2025-08-21 07:11:11 -06:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
Documentation Devicetree fixes for v6.17, part 1: 2025-08-25 18:47:58 -07:00
drivers virtio,vhost: fixes 2025-08-27 10:19:35 -07:00
fs Driver core fixes for 6.16-rc3 2025-08-23 09:04:32 -04:00
include virtio,vhost: fixes 2025-08-27 10:19:35 -07:00
init Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
io_uring io_uring: clear ->async_data as part of normal init 2025-08-21 13:54:01 -06:00
ipc vfs-6.17-rc1.mmap_prepare 2025-07-28 13:43:25 -07:00
kernel - Fix a case where the events throttling logic operates on inactive events 2025-08-24 10:13:05 -04:00
lib Crypto library fixes for v6.17-rc3 2025-08-21 04:54:01 -07:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm Driver core fixes for 6.16-rc3 2025-08-23 09:04:32 -04:00
net netfilter: nf_reject: don't leak dst refcount for loopback packets 2025-08-21 10:02:00 -07:00
rust Driver core fixes for 6.16-rc3 2025-08-23 09:04:32 -04:00
samples Significant patch series in this pull request: 2025-08-03 16:23:09 -07:00
scripts Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
security + Features 2025-08-04 08:17:28 -07:00
sound ALSA: usb-audio: Use correct sub-type for UAC3 feature unit validation 2025-08-21 17:10:14 +02:00
tools perf python: Add evlist compute_metric 2025-09-03 12:34:54 -03:00
usr usr/include: openrisc: don't HDRTEST bpf_perf_event.h 2025-05-12 15:03:17 +09:00
virt Merge tag 'kvm-x86-no_assignment-6.17' of https://github.com/kvm-x86/linux into HEAD 2025-07-29 08:36:42 -04:00
.clang-format Linux 6.15-rc5 2025-05-06 16:39:25 +10:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore gitignore: allow .pylintrc to be tracked 2025-07-02 17:10:04 -06:00
.mailmap .mailmap: add entry for Easwar Hariharan 2025-08-19 16:35:55 -07:00
.pylintrc docs: add a .pylintrc file with sys path for docs scripts 2025-04-09 12:10:33 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS Kbuild updates for v6.17 2025-08-06 07:32:52 +03:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS i2c-for-6.17-rc3 2025-08-24 10:32:04 -04:00
Makefile Linux 6.17-rc3 2025-08-24 12:04:12 -04:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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.