linux-kernel - Re: [PATCH v3 1/2] perf script: Show branch speculation info

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Date:   Mon, 30 Jan 2023 16:04:58 +0530
From:   Sandipan Das <sandipan.das@....com>
To:     linux-kernel@...r.kernel.org, linux-perf-users@...r.kernel.org,
        x86@...nel.org
Cc:     peterz@...radead.org, bp@...en8.de, acme@...nel.org,
        namhyung@...nel.org, jolsa@...nel.org, tglx@...utronix.de,
        mingo@...hat.com, mark.rutland@....com,
        alexander.shishkin@...ux.intel.com, dave.hansen@...ux.intel.com,
        james.clark@....com, irogers@...gle.com, eranian@...gle.com,
        ananth.narayan@....com, ravi.bangoria@....com,
        santosh.shukla@....com
Subject: Re: [PATCH v3 1/2] perf script: Show branch speculation info

On 1/30/2023 11:29 AM, Sandipan Das wrote:
> Show the branch speculation info if provided by the branch recording
> hardware feature. This can be useful for optimizing code further.
> 
> The speculation info is appended to the end of the list of fields so any
> existing tools that use "/" as a delimiter for access fields via an index
> remain unaffected. Also show "-" instead of "N/A" when speculation info
> is unavailable because "/" is used as the field separator.
> 
> E.g.
> 
>   $ perf record -j any,u,save_type ./test_branch
>   $ perf script --fields brstacksym
> 
> Before:
> 
>   [...]
>   check_match+0x60/strcmp+0x0/P/-/-/0/CALL
>   do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL
>   [...]
> 
> After:
> 
>   [...]
>   check_match+0x60/strcmp+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH
>   do_lookup_x+0x3c5/check_match+0x0/P/-/-/0/CALL/NON_SPEC_CORRECT_PATH
>   [...]
> 
> Signed-off-by: Sandipan Das <sandipan.das@....com>
> ---
>  tools/perf/builtin-script.c |  5 +++--
>  tools/perf/util/branch.c    | 15 +++++++++++++++
>  tools/perf/util/branch.h    |  2 ++
>  tools/perf/util/evsel.c     | 15 ++++++++++++---
>  4 files changed, 32 insertions(+), 5 deletions(-)
> 

Sorry but I realized later that this change breaks the builtin branch test.
The additional change below fixes that.

diff --git a/tools/perf/tests/shell/test_brstack.sh b/tools/perf/tests/shell/test_brstack.sh
index 59195eb80052..1c49d8293003 100755
--- a/tools/perf/tests/shell/test_brstack.sh
+++ b/tools/perf/tests/shell/test_brstack.sh
@@ -30,14 +30,14 @@ test_user_branches() {
        #       brstack_foo+0x14/brstack_bar+0x40/P/-/-/0/CALL

        set -x
-       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL$"        $TMPDIR/perf.script
-       grep -E -m1 "^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL$"      $TMPDIR/perf.script
-       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL$"    $TMPDIR/perf.script
-       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL$"    $TMPDIR/perf.script
-       grep -E -m1 "^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET$"               $TMPDIR/perf.script
-       grep -E -m1 "^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET$"     $TMPDIR/perf.script
-       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND$"  $TMPDIR/perf.script
-       grep -E -m1 "^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND$"            $TMPDIR/perf.script
+       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/IND_CALL/.*$"     $TMPDIR/perf.script
+       grep -E -m1 "^brstack_foo\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$"   $TMPDIR/perf.script
+       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_foo\+[^ ]*/CALL/.*$" $TMPDIR/perf.script
+       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_bar\+[^ ]*/CALL/.*$" $TMPDIR/perf.script
+       grep -E -m1 "^brstack_bar\+[^ ]*/brstack_foo\+[^ ]*/RET/.*$"            $TMPDIR/perf.script
+       grep -E -m1 "^brstack_foo\+[^ ]*/brstack_bench\+[^ ]*/RET/.*$"  $TMPDIR/perf.script
+       grep -E -m1 "^brstack_bench\+[^ ]*/brstack_bench\+[^ ]*/COND/.*$"       $TMPDIR/perf.script
+       grep -E -m1 "^brstack\+[^ ]*/brstack\+[^ ]*/UNCOND/.*$"         $TMPDIR/perf.script
        set +x

        # some branch types are still not being tested:
@@ -57,7 +57,7 @@ test_filter() {

        # fail if we find any branch type that doesn't match any of the expected ones
        # also consider UNKNOWN branch types (-)
-       if grep -E -vm1 "^[^ ]*/($expect|-|( *))$" $TMPDIR/perf.script; then
+       if grep -E -vm1 "^[^ ]*/($expect|-|( *))/.*$" $TMPDIR/perf.script; then
                return 1
        fi
 }


- Sandipan