From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Riccardo Mancini <rickyman7@gmail.com>
Cc: Ian Rogers <irogers@google.com>,
Namhyung Kim <namhyung@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Mark Rutland <mark.rutland@arm.com>, Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org
Subject: Re: [RFC PATCH v1 01/37] libperf cpumap: improve idx function
Date: Tue, 31 Aug 2021 15:46:32 -0300 [thread overview]
Message-ID: <YS55COgKH5CRsYE0@kernel.org> (raw)
In-Reply-To: <f1543c15797169c21e8b205a4a6751159180580d.1629490974.git.rickyman7@gmail.com>
Em Sat, Aug 21, 2021 at 11:19:07AM +0200, Riccardo Mancini escreveu:
> >From commit 7074674e7338863e ("perf cpumap: Maintain cpumaps ordered
> and without dups"), perf_cpu_map elements are sorted in ascending order.
>
> This patch improves the perf_cpu_map__idx function by using a binary
> search.
Why not use bsearch()? See 'man bsearch' and look at the example.
- Arnaldo
> Signed-off-by: Riccardo Mancini <rickyman7@gmail.com>
> ---
> tools/lib/perf/cpumap.c | 15 +++++++++++----
> 1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/tools/lib/perf/cpumap.c b/tools/lib/perf/cpumap.c
> index ca0215047c326af4..fb633272be3aaed9 100644
> --- a/tools/lib/perf/cpumap.c
> +++ b/tools/lib/perf/cpumap.c
> @@ -265,11 +265,18 @@ bool perf_cpu_map__empty(const struct perf_cpu_map *map)
>
> int perf_cpu_map__idx(struct perf_cpu_map *cpus, int cpu)
> {
> - int i;
> + int low = 0, high = cpus->nr, idx, cpu_at_idx;
>
> - for (i = 0; i < cpus->nr; ++i) {
> - if (cpus->map[i] == cpu)
> - return i;
> + while (low < high) {
> + idx = (low + high) / 2;
> + cpu_at_idx = cpus->map[idx];
> +
> + if (cpu_at_idx == cpu)
> + return idx;
> + else if (cpu_at_idx > cpu)
> + high = idx;
> + else
> + low = idx+1;
> }
>
> return -1;
> --
> 2.31.1
--
- Arnaldo
next prev parent reply other threads:[~2021-08-31 18:46 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-08-21 9:19 [RFC PATCH v1 00/37] perf: use workqueue for evlist operations Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 01/37] libperf cpumap: improve idx function Riccardo Mancini
2021-08-31 18:46 ` Arnaldo Carvalho de Melo [this message]
2021-10-08 14:29 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 02/37] libperf cpumap: improve max function Riccardo Mancini
2021-08-31 18:47 ` Arnaldo Carvalho de Melo
2021-08-31 19:16 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu Riccardo Mancini
2021-10-08 14:38 ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu() Arnaldo Carvalho de Melo
2021-12-11 0:20 ` [RFC PATCH v1 03/37] perf evlist: replace evsel__cpu_iter* functions with evsel__find_cpu Ian Rogers
2021-08-21 9:19 ` [RFC PATCH v1 04/37] perf util: add mmap_cpu_mask__duplicate function Riccardo Mancini
2021-08-31 19:21 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 05/37] perf util/mmap: add missing bitops.h header Riccardo Mancini
2021-08-31 19:22 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 06/37] perf workqueue: add affinities to threadpool Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 07/37] perf workqueue: add support for setting affinities to workers Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 08/37] perf workqueue: add method to execute work on specific CPU Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 09/37] perf python: add workqueue dependency Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 10/37] perf evlist: add multithreading helper Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 11/37] perf evlist: add multithreading to evlist__disable Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 12/37] perf evlist: add multithreading to evlist__enable Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 13/37] perf evlist: add multithreading to evlist__close Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 14/37] perf evsel: remove retry_sample_id goto label Riccardo Mancini
2021-08-31 19:25 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 15/37] perf evsel: separate open preparation from open itself Riccardo Mancini
2021-08-31 19:27 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 16/37] perf evsel: save open flags in evsel Riccardo Mancini
2021-08-31 19:31 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 17/37] perf evsel: separate missing feature disabling from evsel__open_cpu Riccardo Mancini
2021-08-31 19:35 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 18/37] perf evsel: add evsel__prepare_open function Riccardo Mancini
2021-08-31 19:36 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 19/37] perf evsel: separate missing feature detection from evsel__open_cpu Riccardo Mancini
2021-08-31 19:39 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 20/37] perf evsel: separate rlimit increase " Riccardo Mancini
2021-08-31 19:41 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 21/37] perf evsel: move ignore_missing_thread to fallback code Riccardo Mancini
2021-08-31 19:44 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 22/37] perf evsel: move test_attr__open to success path in evsel__open_cpu Riccardo Mancini
2021-08-31 19:47 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 23/37] perf evsel: move bpf_counter__install_pe " Riccardo Mancini
2021-08-31 19:50 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 24/37] perf evsel: handle precise_ip fallback " Riccardo Mancini
2021-08-31 19:52 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 25/37] perf evsel: move event open in evsel__open_cpu to separate function Riccardo Mancini
2021-08-31 19:54 ` Arnaldo Carvalho de Melo
2021-09-03 21:52 ` Riccardo Mancini
2021-09-11 19:10 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 26/37] perf evsel: add evsel__open_per_cpu_no_fallback function Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 27/37] perf evlist: add evlist__for_each_entry_from macro Riccardo Mancini
2021-08-31 20:06 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 28/37] perf evlist: add multithreading to evlist__open Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 29/37] perf evlist: add custom fallback " Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 30/37] perf record: use evlist__open_custom Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 31/37] tools lib/subcmd: add OPT_UINTEGER_OPTARG option type Riccardo Mancini
2021-08-31 18:44 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 32/37] perf record: add --threads option Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 33/37] perf record: pin threads to monitored cpus if enough threads available Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 34/37] perf record: apply multithreading in init and fini phases Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 35/37] perf test/evlist-open-close: add multithreading Riccardo Mancini
2021-08-21 9:19 ` [RFC PATCH v1 36/37] perf test/evlist-open-close: use inline func to convert timeval to usec Riccardo Mancini
2021-10-08 14:46 ` Arnaldo Carvalho de Melo
2021-08-21 9:19 ` [RFC PATCH v1 37/37] perf test/evlist-open-close: add detailed output mode Riccardo Mancini
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