linux-kernel - Re: [PATCH 4/4] perf script: Output branch sample type

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Message-ID: <3b6007ef-1ad8-c495-26aa-7974af8faefa@arm.com>
Date:   Tue, 8 Mar 2022 10:52:12 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     James Clark <james.clark@....com>, acme@...nel.org,
        linux-perf-users@...r.kernel.org
Cc:     german.gomez@....com, leo.yan@...aro.com,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] perf script: Output branch sample type



On 3/7/22 22:49, James Clark wrote:
> The type info is saved when using '-j save_type'. Output this in perf

Mentioning PERF_SAMPLE_BRANCH_CALL_STACK here as well might be better.

> script so it can be accessed by other tools or for debugging.
> 
> It's appended to the end of the list of fields so any existing tools
> that split on / and access fields via an index are not affected. Also
> output '-' instead of 'N/A' when the branch type isn't saved because /
> is used as a field separator.

Did not get it. Why 'N/A' should have been used anyway ?

> 
> Entries before this change look like this:
> 
>   0xaaaadb350838/0xaaaadb3507a4/P/-/-/0
> 
> And afterwards like this:
> 
>   0xaaaadb350838/0xaaaadb3507a4/P/-/-/0/CALL
> 
> or this if no type info is saved:
> 
>   0x7fb57586df6b/0x7fb5758731f0/P/-/-/143/-

143 ?

> 
> Signed-off-by: James Clark <james.clark@....com>
> ---
>  tools/perf/builtin-script.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
> index fac2e9470926..5e4a262a6825 100644
> --- a/tools/perf/builtin-script.c
> +++ b/tools/perf/builtin-script.c
> @@ -859,11 +859,12 @@ mispred_str(struct branch_entry *br)
>  
>  static int print_bstack_flags(FILE *fp, struct branch_entry *br)
>  {
> -	return fprintf(fp, "/%c/%c/%c/%d ",
> +	return fprintf(fp, "/%c/%c/%c/%d/%s ",
>  		       mispred_str(br),
>  		       br->flags.in_tx ? 'X' : '-',
>  		       br->flags.abort ? 'A' : '-',
> -		       br->flags.cycles);
> +		       br->flags.cycles,
> +		       br->flags.type ? branch_type_name(br->flags.type) : "-");
>  }
>  
>  static int perf_sample__fprintf_brstack(struct perf_sample *sample,


LGTM but as mentioned before, I hope this does not affect any existing
parsing tools.