raspi/linux
1
0
Fork 1
mirror of https://github.com/raspberrypi/linux.git synced 2025-12-24 19:12:14 +00:00
Code Issues Projects Releases Wiki Activity

perf sample: Make user_regs and intr_regs optional

Browse Source 
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>
This commit is contained in:
Ian Rogers
2025-01-13 11:43:45 -08:00
committed by Namhyung Kim
parent 08d9e88348
commit dc6d2bc2d8
34 changed files with 448 additions and 191 deletions
Download Patch File Download Diff File Expand all files Collapse all files

58
tools/perf/tests/sample-parsing.c
View File

@@ -40,8 +40,8 @@
#define BS_EXPECTED_LE 0x1aa00000000
#define FLAG(s) s->branch_stack->entries[i].flags
static bool samples_same(const struct perf_sample *s1,
const struct perf_sample *s2,
static bool samples_same(struct perf_sample *s1,
struct perf_sample *s2,
u64 type, u64 read_format, bool needs_swap)
{
size_t i;
@@ -126,13 +126,15 @@ static bool samples_same(const struct perf_sample *s1,
}
if (type & PERF_SAMPLE_REGS_USER) {
size_t sz = hweight_long(s1->user_regs.mask) * sizeof(u64);
struct regs_dump *s1_regs = perf_sample__user_regs(s1);
struct regs_dump *s2_regs = perf_sample__user_regs(s2);
size_t sz = hweight_long(s1_regs->mask) * sizeof(u64);
COMP(user_regs.mask);
COMP(user_regs.abi);
if (s1->user_regs.abi &&
(!s1->user_regs.regs || !s2->user_regs.regs ||
memcmp(s1->user_regs.regs, s2->user_regs.regs, sz))) {
COMP(user_regs->mask);
COMP(user_regs->abi);
if (s1_regs->abi &&
(!s1_regs->regs || !s2_regs->regs ||
memcmp(s1_regs->regs, s2_regs->regs, sz))) {
pr_debug("Samples differ at 'user_regs'\n");
return false;
}
@@ -157,13 +159,15 @@ static bool samples_same(const struct perf_sample *s1,
COMP(transaction);
if (type & PERF_SAMPLE_REGS_INTR) {
size_t sz = hweight_long(s1->intr_regs.mask) * sizeof(u64);
struct regs_dump *s1_regs = perf_sample__intr_regs(s1);
struct regs_dump *s2_regs = perf_sample__intr_regs(s2);
size_t sz = hweight_long(s1_regs->mask) * sizeof(u64);
COMP(intr_regs.mask);
COMP(intr_regs.abi);
if (s1->intr_regs.abi &&
(!s1->intr_regs.regs || !s2->intr_regs.regs ||
memcmp(s1->intr_regs.regs, s2->intr_regs.regs, sz))) {
COMP(intr_regs->mask);
COMP(intr_regs->abi);
if (s1_regs->abi &&
(!s1_regs->regs || !s2_regs->regs ||
memcmp(s1_regs->regs, s2_regs->regs, sz))) {
pr_debug("Samples differ at 'intr_regs'\n");
return false;
}
@@ -223,6 +227,16 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
const u32 raw_data[] = {0x12345678, 0x0a0b0c0d, 0x11020304, 0x05060708, 0 };
const u64 data[] = {0x2211443366558877ULL, 0, 0xaabbccddeeff4321ULL};
const u64 aux_data[] = {0xa55a, 0, 0xeeddee, 0x0282028202820282};
struct regs_dump user_regs = {
.abi = PERF_SAMPLE_REGS_ABI_64,
.mask = sample_regs,
.regs = regs,
};
struct regs_dump intr_regs = {
.abi = PERF_SAMPLE_REGS_ABI_64,
.mask = sample_regs,
.regs = regs,
};
struct perf_sample sample = {
.ip = 101,
.pid = 102,
@@ -241,11 +255,7 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
.callchain = &callchain.callchain,
.no_hw_idx = false,
.branch_stack = &branch_stack.branch_stack,
.user_regs = {
.abi = PERF_SAMPLE_REGS_ABI_64,
.mask = sample_regs,
.regs = regs,
},
.user_regs = &user_regs,
.user_stack = {
.size = sizeof(data),
.data = (void *)data,
@@ -254,11 +264,7 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
.time_enabled = 0x030a59d664fca7deULL,
.time_running = 0x011b6ae553eb98edULL,
},
.intr_regs = {
.abi = PERF_SAMPLE_REGS_ABI_64,
.mask = sample_regs,
.regs = regs,
},
.intr_regs = &intr_regs,
.phys_addr = 113,
.cgroup = 114,
.data_page_size = 115,
@@ -273,6 +279,8 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
size_t i, sz, bufsz;
int err, ret = -1;
perf_sample__init(&sample_out, /*all=*/false);
perf_sample__init(&sample_out_endian, /*all=*/false);
if (sample_type & PERF_SAMPLE_REGS_USER)
evsel.core.attr.sample_regs_user = sample_regs;
@@ -361,6 +369,8 @@ static int do_test(u64 sample_type, u64 sample_regs, u64 read_format)
ret = 0;
out_free:
free(event);
perf_sample__exit(&sample_out_endian);
perf_sample__exit(&sample_out);
if (ret && read_format)
pr_debug("read_format %#"PRIx64"\n", read_format);
return ret;