linux-kernel - Re: [PATCH v1 0/3] Metric related performance improvements

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Message-ID: <CAP-5=fU6NM4LZWt9SdTFX9JKTgfghwAVvtXc-qBuUb0vpUeTQA@mail.gmail.com>
Date: Wed, 23 Apr 2025 13:48:22 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	James Clark <james.clark@...aro.org>, Xu Yang <xu.yang_2@....com>, 
	John Garry <john.g.garry@...cle.com>, Dominique Martinet <asmadeus@...ewreck.org>, 
	Thomas Richter <tmricht@...ux.ibm.com>, Weilin Wang <weilin.wang@...el.com>, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 0/3] Metric related performance improvements

On Wed, Apr 9, 2025 at 11:49 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> Hi Ian,
>
> On Wed, Apr 09, 2025 at 09:45:29PM -0700, Ian Rogers wrote:
> > The "PMU JSON event tests" have been running slowly, these changes
> > target improving them with an improvement of the test running 8 to 10
> > times faster.
> >
> > The first patch changes from searching through all aliases by name in
> > a list to using a hashmap. Doing a fast hashmap__find means testing
> > for having an event needn't load from disk if an event is already
> > present.
> >
> > The second patch switch the fncache to use a hashmap rather than its
> > own hashmap with a limited number of buckets. When there are many
> > filename queries, such as with a test, there are many collisions with
> > the previous fncache approach leading to linear searching of the
> > entries.
> >
> > The final patch adds a find function for metrics. Normally metrics can
> > match by name and group, however, only name matching happens when one
> > metric refers to another. As we test every "id" in a metric to see if
> > it is a metric, the find function can dominate performance as it
> > linearly searches all metrics. Add a find function for the metrics
> > table so that a metric can be found by name with a binary search.
> >
> > Before these changes:
> > ```
> > $ time perf test -v 10
> >  10: PMU JSON event tests                                            :
> >  10.1: PMU event table sanity                                        : Ok
> >  10.2: PMU event map aliases                                         : Ok
> >  10.3: Parsing of PMU event table metrics                            : Ok
> >  10.4: Parsing of PMU event table metrics with fake PMUs             : Ok
> >  10.5: Parsing of metric thresholds with fake PMUs                   : Ok
> >
> > real    0m18.499s
> > user    0m18.150s
> > sys     0m3.273s
> > ```
> >
> > After these changes:
> > ```
> > $ time perf test -v 10
> >  10: PMU JSON event tests                                            :
> >  10.1: PMU event table sanity                                        : Ok
> >  10.2: PMU event map aliases                                         : Ok
> >  10.3: Parsing of PMU event table metrics                            : Ok
> >  10.4: Parsing of PMU event table metrics with fake PMUs             : Ok
> >  10.5: Parsing of metric thresholds with fake PMUs                   : Ok
> >
> > real    0m2.338s
> > user    0m1.797s
> > sys     0m2.186s
> > ```
>
> Great, I also see the speedup on my machine from 32s to 3s.
>
> Tested-by: Namhyung Kim <namhyung@...nel.org>

Ping.

Thanks,
Ian

> Thanks,
> Namhyung
>
> >
> > Ian Rogers (3):
> >   perf pmu: Change aliases from list to hashmap
> >   perf fncache: Switch to using hashmap
> >   perf metricgroup: Binary search when resolving referred to metrics
> >
> >  tools/perf/builtin-stat.c                |   6 +-
> >  tools/perf/pmu-events/empty-pmu-events.c |  66 ++++++++-
> >  tools/perf/pmu-events/jevents.py         |  66 ++++++++-
> >  tools/perf/pmu-events/pmu-events.h       |  23 +++-
> >  tools/perf/tests/pmu-events.c            | 129 +++++++++--------
> >  tools/perf/util/fncache.c                |  69 +++++-----
> >  tools/perf/util/fncache.h                |   1 -
> >  tools/perf/util/hwmon_pmu.c              |  43 +++---
> >  tools/perf/util/metricgroup.c            | 102 ++++++--------
> >  tools/perf/util/metricgroup.h            |   2 +-
> >  tools/perf/util/pmu.c                    | 167 +++++++++++++++--------
> >  tools/perf/util/pmu.h                    |   4 +-
> >  tools/perf/util/srccode.c                |   4 +-
> >  tools/perf/util/tool_pmu.c               |  17 +--
> >  14 files changed, 430 insertions(+), 269 deletions(-)
> >
> > --
> > 2.49.0.504.g3bcea36a83-goog
> >