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/tests/code-reading.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'tools/perf/tests/code-reading.c') diff --git a/tools/perf/tests/code-reading.c b/tools/perf/tests/code-reading.c index b1abb34d7818..cf6edbe697b2 100644 --- a/tools/perf/tests/code-reading.c +++ b/tools/perf/tests/code-reading.c @@ -479,19 +479,25 @@ static int process_sample_event(struct machine *machine, struct thread *thread; int ret; - if (evlist__parse_sample(evlist, event, &sample)) { + perf_sample__init(&sample, /*all=*/false); + ret = evlist__parse_sample(evlist, event, &sample); + if (ret) { pr_debug("evlist__parse_sample failed\n"); - return -1; + ret = -1; + goto out; } thread = machine__findnew_thread(machine, sample.pid, sample.tid); if (!thread) { pr_debug("machine__findnew_thread failed\n"); - return -1; + ret = -1; + goto out; } ret = read_object_code(sample.ip, READLEN, sample.cpumode, thread, state); thread__put(thread); +out: + perf_sample__exit(&sample); return ret; } -- cgit v1.2.3