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

From: Sandipan Das
Date: Mon Jan 30 2023 - 05:35:22 EST


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@xxxxxxx>
> ---
> 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