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From:   Namhyung Kim <namhyung@kernel.org>
Date:   Wed, 5 Jul 2023 22:55:52 -0700
Message-ID: <CAM9d7ciAeGJ=n6DiR9=0K1AmN1mLoYXqYVjFFEPPD8UnRrstoA@mail.gmail.com>
Subject: Re: [PATCH v2 4/7] scripts: python: implement get or create stack function
To:     Anup Sharma <anupnewsmail@gmail.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
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On Wed, Jul 5, 2023 at 12:48 PM Anup Sharma <anupnewsmail@gmail.com> wrote:
>
> The get_or_create_stack function is responsible for retrieving
> or creating a stack based on the provided frame and prefix.
> It first generates a key using the frame and prefix values.
> If the stack corresponding to the key is found in the stackMap,
> it is returned. Otherwise, a new stack is created by appending
> the prefix and frame to the stackTable's 'data' array. The key
> and the index of the newly created stack are added to the
> stackMap for future reference.
>
> Signed-off-by: Anup Sharma <anupnewsmail@gmail.com>
> ---
>  tools/perf/scripts/python/firefox-gecko-converter.py | 11 +++++++++++
>  1 file changed, 11 insertions(+)
>
> diff --git a/tools/perf/scripts/python/firefox-gecko-converter.py b/tools/perf/scripts/python/firefox-gecko-converter.py
> index e56864e78dc1..6f69c083d3ff 100644
> --- a/tools/perf/scripts/python/firefox-gecko-converter.py
> +++ b/tools/perf/scripts/python/firefox-gecko-converter.py
> @@ -65,6 +65,17 @@ def process_event(param_dict):
>                         },
>                         'data': [],
>                 }
> +               stringTable = []
> +
> +               stackMap = dict()
> +               def get_or_create_stack(frame, prefix):
> +                       key = f"{frame}" if prefix is None else f"{frame},{prefix}"
> +                       stack = stackMap.get(key)

I'm confused about what the 'stack' is.

> +                       if stack is None:
> +                               stack = len(stackTable['data'])

It seems like a kind of index for the stackTable's data.

> +                               stackTable['data'].append([prefix, frame])
> +                               stackMap[key] = stack
> +                       return stack

So this function returns an index, right?

Thanks,
Namhyung


>
>         def _addThreadSample(pid, tid, threadName, time_stamp, stack):
>                 thread = thread_map.get(tid)
> --
> 2.34.1
>