diff options
| author | Ian Rogers <irogers@google.com> | 2025-01-13 11:43:45 -0800 |
|---|---|---|
| committer | Namhyung Kim <namhyung@kernel.org> | 2025-02-12 20:06:11 -0800 |
| commit | dc6d2bc2d893a878e7b58578ff01b4738708deb4 (patch) | |
| tree | b5524ff4429f1e88533f518753091462bc4bd8b4 /tools/perf/arch | |
| parent | 08d9e883481b2c38326ed37314b1f6a1284c03d8 (diff) | |
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/arch')
| -rw-r--r-- | tools/perf/arch/x86/tests/dwarf-unwind.c | 2 | ||||
| -rw-r--r-- | tools/perf/arch/x86/util/unwind-libdw.c | 2 |
2 files changed, 2 insertions, 2 deletions
diff --git a/tools/perf/arch/x86/tests/dwarf-unwind.c b/tools/perf/arch/x86/tests/dwarf-unwind.c index c05c0a85dad41..e91a73d09cecf 100644 --- a/tools/perf/arch/x86/tests/dwarf-unwind.c +++ b/tools/perf/arch/x86/tests/dwarf-unwind.c @@ -53,7 +53,7 @@ static int sample_ustack(struct perf_sample *sample, int test__arch_unwind_sample(struct perf_sample *sample, struct thread *thread) { - struct regs_dump *regs = &sample->user_regs; + struct regs_dump *regs = perf_sample__user_regs(sample); u64 *buf; buf = malloc(sizeof(u64) * PERF_REGS_MAX); diff --git a/tools/perf/arch/x86/util/unwind-libdw.c b/tools/perf/arch/x86/util/unwind-libdw.c index edb77e20e0832..798493e887d73 100644 --- a/tools/perf/arch/x86/util/unwind-libdw.c +++ b/tools/perf/arch/x86/util/unwind-libdw.c @@ -8,7 +8,7 @@ bool libdw__arch_set_initial_registers(Dwfl_Thread *thread, void *arg) { struct unwind_info *ui = arg; - struct regs_dump *user_regs = &ui->sample->user_regs; + struct regs_dump *user_regs = perf_sample__user_regs(ui->sample); Dwarf_Word dwarf_regs[17]; unsigned nregs; |