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SubjectRe: [PATCH 2/4] perf: Print branch stack entry type in --dump-raw-trace
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On 3/7/22 22:49, James Clark wrote:
> This can help with debugging issues. It only prints when -j save_type
> is used otherwise an empty string is printed.

Specifying events with PERF_SAMPLE_BRANCH_CALL_STACK flag explicitly might
be better along with '-j save_type'.

>
> Before the change:
>
> 101603801707130 0xa70 [0x630]: PERF_RECORD_SAMPLE(IP, 0x2): 1108/1108: 0xffff9c1df24c period: 10694 addr: 0
> ... branch stack: nr:64
> ..... 0: 0000ffff9c26029c -> 0000ffff9c26f340 0 cycles P 0
> ..... 1: 0000ffff9c2601bc -> 0000ffff9c26f340 0 cycles P 0
>
> After the change:
>
> 101603801707130 0xa70 [0x630]: PERF_RECORD_SAMPLE(IP, 0x2): 1108/1108: 0xffff9c1df24c period: 10694 addr: 0
> ... branch stack: nr:64
> ..... 0: 0000ffff9c26029c -> 0000ffff9c26f340 0 cycles P 0 CALL
> ..... 1: 0000ffff9c2601bc -> 0000ffff9c26f340 0 cycles P 0 IND_CALL
>
> Signed-off-by: James Clark <james.clark@arm.com>
> ---
> tools/perf/util/session.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index f54282d5c648..3b8dfe603e50 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1159,14 +1159,15 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
> struct branch_entry *e = &entries[i];
>
> if (!callstack) {
> - printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 " %hu cycles %s%s%s%s %x\n",
> + printf("..... %2"PRIu64": %016" PRIx64 " -> %016" PRIx64 " %hu cycles %s%s%s%s %x %s\n",
> i, e->from, e->to,
> (unsigned short)e->flags.cycles,
> e->flags.mispred ? "M" : " ",
> e->flags.predicted ? "P" : " ",
> e->flags.abort ? "A" : " ",
> e->flags.in_tx ? "T" : " ",
> - (unsigned)e->flags.reserved);
> + (unsigned)e->flags.reserved,
> + e->flags.type ? branch_type_name(e->flags.type) : "");
> } else {
> printf("..... %2"PRIu64": %016" PRIx64 "\n",
> i, i > 0 ? e->from : e->to);

LGTM but I am wondering whether this might affect existing tools ?

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