| 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
| ||
|
Message-ID: <CAP-5=fXsrKvKAtAW3b-OzAdzg00hW-py-9eMvCxoY3Vs4p+7iw@mail.gmail.com>
Date: Wed, 10 Dec 2025 14:05:23 -0800
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>, James Clark <james.clark@...aro.org>,
Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>, linux-perf-users@...r.kernel.org
Subject: Re: [PATCH 1/4] perf record: Split --data-mmap option
On Tue, Dec 9, 2025 at 6:33 PM Namhyung Kim <namhyung@...nel.org> wrote:
>
> Currently -d/--data option controls both PERF_SAMPLE_ADDR bit and
> perf_event_attr.mmap_data flag. Separate them using new --data-mmap
> option to support recording only one of them.
>
> For data-type profiling, data MMAP is unnecessary but it wastes a lot
> of space in the ring buffer and data file.
>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
Reviewed-by: Ian Rogers <irogers@...gle.com>
Thanks,
Ian
> ---
> tools/perf/Documentation/perf-record.txt | 8 +++++++-
> tools/perf/builtin-record.c | 19 +++++++++++++------
> tools/perf/util/evsel.c | 5 +++--
> tools/perf/util/record.h | 2 ++
> 4 files changed, 25 insertions(+), 9 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> index e8b9aadbbfa50574..c402e74172f6a22d 100644
> --- a/tools/perf/Documentation/perf-record.txt
> +++ b/tools/perf/Documentation/perf-record.txt
> @@ -344,7 +344,8 @@ OPTIONS
>
> -d::
> --data::
> - Record the sample virtual addresses. Implies --sample-mem-info.
> + Record the sample virtual addresses. Implies --sample-mem-info and
> + --data-mmap.
>
> --phys-data::
> Record the sample physical addresses.
> @@ -861,6 +862,11 @@ filtered through the mask provided by -C option.
> Prepare BPF filter to be used by regular users. The action should be
> either "pin" or "unpin". The filter can be used after it's pinned.
>
> +--data-mmap::
> + Enable recording MMAP events for non-executable mappings. Basically
> + perf only records executable mappings but data mmaping can be useful
> + when you analyze data access with sample addresses. So using -d option
> + would enable this unless you specify --no-data-mmap manually.
>
> include::intel-hybrid.txt[]
>
> diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> index 2584d0d8bc820676..cbfbd9bb10634093 100644
> --- a/tools/perf/builtin-record.c
> +++ b/tools/perf/builtin-record.c
> @@ -1881,7 +1881,7 @@ static int record__synthesize_workload(struct record *rec, bool tail)
> process_synthesized_event,
> &rec->session->machines.host,
> needs_mmap,
> - rec->opts.sample_address);
> + rec->opts.record_data_mmap);
> perf_thread_map__put(thread_map);
> return err;
> }
> @@ -2191,7 +2191,7 @@ static int record__synthesize(struct record *rec, bool tail)
>
> err = __machine__synthesize_threads(machine, tool, &opts->target,
> rec->evlist->core.threads,
> - f, needs_mmap, opts->sample_address,
> + f, needs_mmap, opts->record_data_mmap,
> rec->opts.nr_threads_synthesize);
> }
>
> @@ -3006,8 +3006,9 @@ int record_opts__parse_callchain(struct record_opts *record,
> ret = parse_callchain_record_opt(arg, callchain);
> if (!ret) {
> /* Enable data address sampling for DWARF unwind. */
> - if (callchain->record_mode == CALLCHAIN_DWARF)
> - record->sample_address = true;
> + if (callchain->record_mode == CALLCHAIN_DWARF &&
> + !record->record_data_mmap_set)
> + record->record_data_mmap = true;
> callchain_debug(callchain);
> }
>
> @@ -3686,6 +3687,9 @@ static struct option __record_options[] = {
> OPT_CALLBACK(0, "off-cpu-thresh", &record.opts, "ms",
> "Dump off-cpu samples if off-cpu time exceeds this threshold (in milliseconds). (Default: 500ms)",
> record__parse_off_cpu_thresh),
> + OPT_BOOLEAN_SET(0, "data-mmap", &record.opts.record_data_mmap,
> + &record.opts.record_data_mmap_set,
> + "Record mmap events for non-executable mappings"),
> OPT_END()
> };
>
> @@ -4249,9 +4253,12 @@ int cmd_record(int argc, const char **argv)
> goto out_opts;
> }
>
> - /* For backward compatibility, -d implies --mem-info */
> - if (rec->opts.sample_address)
> + /* For backward compatibility, -d implies --mem-info and --data-mmap */
> + if (rec->opts.sample_address) {
> rec->opts.sample_data_src = true;
> + if (!rec->opts.record_data_mmap_set)
> + rec->opts.record_data_mmap = true;
> + }
>
> /*
> * Allow aliases to facilitate the lookup of symbols for address
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 9cd706f6279313c2..ec6552a6f667fec6 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -1445,10 +1445,11 @@ void evsel__config(struct evsel *evsel, struct record_opts *opts,
> attr->inherit_stat = 1;
> }
>
> - if (opts->sample_address) {
> + if (opts->sample_address)
> evsel__set_sample_bit(evsel, ADDR);
> +
> + if (opts->record_data_mmap)
> attr->mmap_data = track;
> - }
>
> /*
> * We don't allow user space callchains for function trace
> diff --git a/tools/perf/util/record.h b/tools/perf/util/record.h
> index ea3a6c4657eefb74..93627c9a73387ddd 100644
> --- a/tools/perf/util/record.h
> +++ b/tools/perf/util/record.h
> @@ -40,6 +40,8 @@ struct record_opts {
> bool record_cgroup;
> bool record_switch_events;
> bool record_switch_events_set;
> + bool record_data_mmap;
> + bool record_data_mmap_set;
> bool all_kernel;
> bool all_user;
> bool kernel_callchains;
> --
> 2.52.0.223.gf5cc29aaa4-goog
>
Powered by blists - more mailing lists