linux-kernel - Re: [PATCH v1] perf trace: Don't synthesize mmaps unless callchains are enabled

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Message-ID: <CAH0uvohAneSDaXoDfNdOhg8Osnk4AYye4B59zhS=NaGj4upM5A@mail.gmail.com>
Date: Fri, 17 Oct 2025 22:19:37 -0700
From: Howard Chu <howardchu95@...il.com>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, linux-perf-users@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Stephane Eranian <eranian@...gle.com>
Subject: Re: [PATCH v1] perf trace: Don't synthesize mmaps unless callchains
 are enabled

Hi Ian,

(It's been a while, forgot to switch on plain text mode)

On Fri, Oct 17, 2025 at 9:59 PM Ian Rogers <irogers@...gle.com> wrote:
>
> Synthesizing mmaps in perf trace is unnecessary unless call chains are
> being generated.
>
> Signed-off-by: Ian Rogers <irogers@...gle.com>

Acked-by: Howard Chu <howardchu95@...il.com>

Thanks,
Howard

> ---
>  tools/perf/builtin-trace.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c
> index c607f39b8c8b..a743bda294bd 100644
> --- a/tools/perf/builtin-trace.c
> +++ b/tools/perf/builtin-trace.c
> @@ -2005,7 +2005,9 @@ static int trace__symbols_init(struct trace *trace, int argc, const char **argv,
>
>         err = __machine__synthesize_threads(trace->host, &trace->tool, &trace->opts.target,
>                                             evlist->core.threads, trace__tool_process,
> -                                           true, false, 1);
> +                                           /*needs_mmap=*/callchain_param.enabled,
> +                                           /*mmap_data=*/false,
> +                                           /*nr_threads_synthesize=*/1);
>  out:
>         if (err) {
>                 perf_env__exit(&trace->host_env);
> --
> 2.51.0.858.gf9c4a03a3a-goog
>
>