diff options
| author | Ian Rogers <irogers@google.com> | 2025-01-13 22:43:45 +0300 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-02-13 07:06:11 +0300 |
| commit | dc6d2bc2d893a878e7b58578ff01b4738708deb4 (patch) | |
| tree | b5524ff4429f1e88533f518753091462bc4bd8b4 /tools/perf/util/intel-bts.c | |
| parent | 08d9e883481b2c38326ed37314b1f6a1284c03d8 (diff) | |
| download | linux-dc6d2bc2d893a878e7b58578ff01b4738708deb4.tar.xz | |
perf sample: Make user_regs and intr_regs optional
The struct dump_regs contains 512 bytes of cache_regs, meaning the two
values in perf_sample contribute 1088 bytes of its total 1384 bytes
size. Initializing this much memory has a cost reported by Tavian
Barnes <tavianator@tavianator.com> as about 2.5% when running `perf
script --itrace=i0`:
https://lore.kernel.org/lkml/d841b97b3ad2ca8bcab07e4293375fb7c32dfce7.1736618095.git.tavianator@tavianator.com/
Adrian Hunter <adrian.hunter@intel.com> replied that the zero
initialization was necessary and couldn't simply be removed.
This patch aims to strike a middle ground of still zeroing the
perf_sample, but removing 79% of its size by make user_regs and
intr_regs optional pointers to zalloc-ed memory. To support the
allocation accessors are created for user_regs and intr_regs. To
support correct cleanup perf_sample__init and perf_sample__exit
functions are created and added throughout the code base.
Signed-off-by: Ian Rogers <irogers@google.com>
Link: https://lore.kernel.org/r/20250113194345.1537821-1-irogers@google.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Diffstat (limited to 'tools/perf/util/intel-bts.c')
| -rw-r--r-- | tools/perf/util/intel-bts.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/tools/perf/util/intel-bts.c b/tools/perf/util/intel-bts.c index a7c589fecb98..3625c6224750 100644 --- a/tools/perf/util/intel-bts.c +++ b/tools/perf/util/intel-bts.c @@ -275,12 +275,13 @@ static int intel_bts_synth_branch_sample(struct intel_bts_queue *btsq, int ret; struct intel_bts *bts = btsq->bts; union perf_event event; - struct perf_sample sample = { .ip = 0, }; + struct perf_sample sample; if (bts->synth_opts.initial_skip && bts->num_events++ <= bts->synth_opts.initial_skip) return 0; + perf_sample__init(&sample, /*all=*/true); sample.ip = le64_to_cpu(branch->from); sample.cpumode = intel_bts_cpumode(bts, sample.ip); sample.pid = btsq->pid; @@ -312,6 +313,7 @@ static int intel_bts_synth_branch_sample(struct intel_bts_queue *btsq, pr_err("Intel BTS: failed to deliver branch event, error %d\n", ret); + perf_sample__exit(&sample); return ret; } |