From dc6d2bc2d893a878e7b58578ff01b4738708deb4 Mon Sep 17 00:00:00 2001 From: Ian Rogers Date: Mon, 13 Jan 2025 11:43:45 -0800 Subject: 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 as about 2.5% when running `perf script --itrace=i0`: https://lore.kernel.org/lkml/d841b97b3ad2ca8bcab07e4293375fb7c32dfce7.1736618095.git.tavianator@tavianator.com/ Adrian Hunter 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 Link: https://lore.kernel.org/r/20250113194345.1537821-1-irogers@google.com Signed-off-by: Namhyung Kim --- tools/perf/util/jitdump.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'tools/perf/util/jitdump.c') diff --git a/tools/perf/util/jitdump.c b/tools/perf/util/jitdump.c index f23e21502bf8..624964f01b5f 100644 --- a/tools/perf/util/jitdump.c +++ b/tools/perf/util/jitdump.c @@ -516,7 +516,7 @@ static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr) * create pseudo sample to induce dso hit increment * use first address as sample address */ - memset(&sample, 0, sizeof(sample)); + perf_sample__init(&sample, /*all=*/true); sample.cpumode = PERF_RECORD_MISC_USER; sample.pid = pid; sample.tid = tid; @@ -535,6 +535,7 @@ static int jit_repipe_code_load(struct jit_buf_desc *jd, union jr_entry *jr) build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine); out: + perf_sample__exit(&sample); free(event); return ret; } @@ -611,7 +612,7 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr) * create pseudo sample to induce dso hit increment * use first address as sample address */ - memset(&sample, 0, sizeof(sample)); + perf_sample__init(&sample, /*all=*/true); sample.cpumode = PERF_RECORD_MISC_USER; sample.pid = pid; sample.tid = tid; @@ -620,12 +621,13 @@ static int jit_repipe_code_move(struct jit_buf_desc *jd, union jr_entry *jr) ret = perf_event__process_mmap2(tool, event, &sample, jd->machine); if (ret) - return ret; + goto out; ret = jit_inject_event(jd, event); if (!ret) build_id__mark_dso_hit(tool, event, &sample, NULL, jd->machine); - +out: + perf_sample__exit(&sample); return ret; } -- cgit v1.2.3-59-g8ed1b