tools/perf/util/session.c | 26 +++++++++++++++++++++----- 1 file changed, 21 insertions(+), 5 deletions(-)
From: Chengdong Li <chengdongli@tencent.com>
when generating callstack information from branch_stack(Intel LBR),
the actual number of callstack entry should be bigger than the number
of branch_stack, for example:
branch_stack records:
B() -> C()
A() -> B()
converted callstack records should be:
C()
B()
A()
though, the number of callstack equals
to the number of branch stack plus 1.
This patch fixes above issue in branch_stack__printf(). For example,
# echo 'scale=2000; 4*a(1)' > cmd
# perf record --call-graph lbr bc -l < cmd
Before applying this patch, `perf script -D` output:
1220022677386876 0x2a40 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x4002): 17990/17990: 0x40a6d6 period: 894172 addr: 0
... LBR call chain: nr:8
..... 0: fffffffffffffe00
..... 1: 000000000040a410
..... 2: 000000000040573c
..... 3: 0000000000408650
..... 4: 00000000004022f2
..... 5: 00000000004015f5
..... 6: 00007f5ed6dcb553
..... 7: 0000000000401698
... FP chain: nr:2
..... 0: fffffffffffffe00
..... 1: 000000000040a6d8
... branch callstack: nr:6 # which is not consistent with LBR records.
..... 0: 000000000040a410
..... 1: 0000000000408650 # ditto
..... 2: 00000000004022f2
..... 3: 00000000004015f5
..... 4: 00007f5ed6dcb553
..... 5: 0000000000401698
... thread: bc:17990
...... dso: /usr/bin/bc
bc 17990 1220022.677386: 894172 cycles:
40a410 [unknown] (/usr/bin/bc)
40573c [unknown] (/usr/bin/bc)
408650 [unknown] (/usr/bin/bc)
4022f2 [unknown] (/usr/bin/bc)
4015f5 [unknown] (/usr/bin/bc)
7f5ed6dcb553 __libc_start_main+0xf3 (/usr/lib64/libc-2.17.so)
401698 [unknown] (/usr/bin/bc)
After applied:
1220022677386876 0x2a40 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x4002): 17990/17990: 0x40a6d6 period: 894172 addr: 0
... LBR call chain: nr:8
..... 0: fffffffffffffe00
..... 1: 000000000040a410
..... 2: 000000000040573c
..... 3: 0000000000408650
..... 4: 00000000004022f2
..... 5: 00000000004015f5
..... 6: 00007f5ed6dcb553
..... 7: 0000000000401698
... FP chain: nr:2
..... 0: fffffffffffffe00
..... 1: 000000000040a6d8
... branch callstack: nr:7
..... 0: 000000000040a410
..... 1: 000000000040573c
..... 2: 0000000000408650
..... 3: 00000000004022f2
..... 4: 00000000004015f5
..... 5: 00007f5ed6dcb553
..... 6: 0000000000401698
... thread: bc:17990
...... dso: /usr/bin/bc
bc 17990 1220022.677386: 894172 cycles:
40a410 [unknown] (/usr/bin/bc)
40573c [unknown] (/usr/bin/bc)
408650 [unknown] (/usr/bin/bc)
4022f2 [unknown] (/usr/bin/bc)
4015f5 [unknown] (/usr/bin/bc)
7f5ed6dcb553 __libc_start_main+0xf3 (/usr/lib64/libc-2.17.so)
401698 [unknown] (/usr/bin/bc)
Change from v1:
- refined code style according to Jiri's review comments.
Signed-off-by: Chengdong Li <chengdongli@tencent.com>
---
tools/perf/util/session.c | 26 +++++++++++++++++++++-----
1 file changed, 21 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index f9a320694b85..a7f93f5a1ac8 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1151,9 +1151,20 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
struct branch_entry *entries = perf_sample__branch_entries(sample);
uint64_t i;
- printf("%s: nr:%" PRIu64 "\n",
- !callstack ? "... branch stack" : "... branch callstack",
- sample->branch_stack->nr);
+ if (!callstack) {
+ printf("%s: nr:%" PRIu64 "\n", "... branch stack", sample->branch_stack->nr);
+ } else {
+ /* the reason of adding 1 to nr is because after expanding
+ * branch stack it generates nr + 1 callstack records. e.g.,
+ * B()->C()
+ * A()->B()
+ * the final callstack should be:
+ * C()
+ * B()
+ * A()
+ */
+ printf("%s: nr:%" PRIu64 "\n", "... branch callstack", sample->branch_stack->nr+1);
+ }
for (i = 0; i < sample->branch_stack->nr; i++) {
struct branch_entry *e = &entries[i];
@@ -1169,8 +1180,13 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
(unsigned)e->flags.reserved,
e->flags.type ? branch_type_name(e->flags.type) : "");
} else {
- printf("..... %2"PRIu64": %016" PRIx64 "\n",
- i, i > 0 ? e->from : e->to);
+ if (i == 0) {
+ printf("..... %2"PRIu64": %016" PRIx64 "\n"
+ "..... %2"PRIu64": %016" PRIx64 "\n",
+ i, e->to, i+1, e->from);
+ } else {
+ printf("..... %2"PRIu64": %016" PRIx64 "\n", i+1, e->from);
+ }
}
}
}
--
2.27.0Hello,
On Mon, May 16, 2022 at 6:57 PM Chengdong Li <brytonlee01@gmail.com> wrote:
>
> From: Chengdong Li <chengdongli@tencent.com>
>
> when generating callstack information from branch_stack(Intel LBR),
> the actual number of callstack entry should be bigger than the number
> of branch_stack, for example:
>
> branch_stack records:
> B() -> C()
> A() -> B()
> converted callstack records should be:
> C()
> B()
> A()
> though, the number of callstack equals
> to the number of branch stack plus 1.
>
> This patch fixes above issue in branch_stack__printf(). For example,
>
> # echo 'scale=2000; 4*a(1)' > cmd
> # perf record --call-graph lbr bc -l < cmd
>
> Before applying this patch, `perf script -D` output:
>
> 1220022677386876 0x2a40 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x4002): 17990/17990: 0x40a6d6 period: 894172 addr: 0
> ... LBR call chain: nr:8
> ..... 0: fffffffffffffe00
> ..... 1: 000000000040a410
> ..... 2: 000000000040573c
> ..... 3: 0000000000408650
> ..... 4: 00000000004022f2
> ..... 5: 00000000004015f5
> ..... 6: 00007f5ed6dcb553
> ..... 7: 0000000000401698
> ... FP chain: nr:2
> ..... 0: fffffffffffffe00
> ..... 1: 000000000040a6d8
> ... branch callstack: nr:6 # which is not consistent with LBR records.
> ..... 0: 000000000040a410
> ..... 1: 0000000000408650 # ditto
> ..... 2: 00000000004022f2
> ..... 3: 00000000004015f5
> ..... 4: 00007f5ed6dcb553
> ..... 5: 0000000000401698
> ... thread: bc:17990
> ...... dso: /usr/bin/bc
> bc 17990 1220022.677386: 894172 cycles:
> 40a410 [unknown] (/usr/bin/bc)
> 40573c [unknown] (/usr/bin/bc)
> 408650 [unknown] (/usr/bin/bc)
> 4022f2 [unknown] (/usr/bin/bc)
> 4015f5 [unknown] (/usr/bin/bc)
> 7f5ed6dcb553 __libc_start_main+0xf3 (/usr/lib64/libc-2.17.so)
> 401698 [unknown] (/usr/bin/bc)
>
> After applied:
>
> 1220022677386876 0x2a40 [0xd8]: PERF_RECORD_SAMPLE(IP, 0x4002): 17990/17990: 0x40a6d6 period: 894172 addr: 0
> ... LBR call chain: nr:8
> ..... 0: fffffffffffffe00
> ..... 1: 000000000040a410
> ..... 2: 000000000040573c
> ..... 3: 0000000000408650
> ..... 4: 00000000004022f2
> ..... 5: 00000000004015f5
> ..... 6: 00007f5ed6dcb553
> ..... 7: 0000000000401698
> ... FP chain: nr:2
> ..... 0: fffffffffffffe00
> ..... 1: 000000000040a6d8
> ... branch callstack: nr:7
> ..... 0: 000000000040a410
> ..... 1: 000000000040573c
> ..... 2: 0000000000408650
> ..... 3: 00000000004022f2
> ..... 4: 00000000004015f5
> ..... 5: 00007f5ed6dcb553
> ..... 6: 0000000000401698
> ... thread: bc:17990
> ...... dso: /usr/bin/bc
> bc 17990 1220022.677386: 894172 cycles:
> 40a410 [unknown] (/usr/bin/bc)
> 40573c [unknown] (/usr/bin/bc)
> 408650 [unknown] (/usr/bin/bc)
> 4022f2 [unknown] (/usr/bin/bc)
> 4015f5 [unknown] (/usr/bin/bc)
> 7f5ed6dcb553 __libc_start_main+0xf3 (/usr/lib64/libc-2.17.so)
> 401698 [unknown] (/usr/bin/bc)
>
> Change from v1:
> - refined code style according to Jiri's review comments.
>
> Signed-off-by: Chengdong Li <chengdongli@tencent.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Thanks,
Namhyung
> ---
> tools/perf/util/session.c | 26 +++++++++++++++++++++-----
> 1 file changed, 21 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
> index f9a320694b85..a7f93f5a1ac8 100644
> --- a/tools/perf/util/session.c
> +++ b/tools/perf/util/session.c
> @@ -1151,9 +1151,20 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
> struct branch_entry *entries = perf_sample__branch_entries(sample);
> uint64_t i;
>
> - printf("%s: nr:%" PRIu64 "\n",
> - !callstack ? "... branch stack" : "... branch callstack",
> - sample->branch_stack->nr);
> + if (!callstack) {
> + printf("%s: nr:%" PRIu64 "\n", "... branch stack", sample->branch_stack->nr);
> + } else {
> + /* the reason of adding 1 to nr is because after expanding
> + * branch stack it generates nr + 1 callstack records. e.g.,
> + * B()->C()
> + * A()->B()
> + * the final callstack should be:
> + * C()
> + * B()
> + * A()
> + */
> + printf("%s: nr:%" PRIu64 "\n", "... branch callstack", sample->branch_stack->nr+1);
> + }
>
> for (i = 0; i < sample->branch_stack->nr; i++) {
> struct branch_entry *e = &entries[i];
> @@ -1169,8 +1180,13 @@ static void branch_stack__printf(struct perf_sample *sample, bool callstack)
> (unsigned)e->flags.reserved,
> e->flags.type ? branch_type_name(e->flags.type) : "");
> } else {
> - printf("..... %2"PRIu64": %016" PRIx64 "\n",
> - i, i > 0 ? e->from : e->to);
> + if (i == 0) {
> + printf("..... %2"PRIu64": %016" PRIx64 "\n"
> + "..... %2"PRIu64": %016" PRIx64 "\n",
> + i, e->to, i+1, e->from);
> + } else {
> + printf("..... %2"PRIu64": %016" PRIx64 "\n", i+1, e->from);
> + }
> }
> }
> }
> --
> 2.27.0
>
Em Tue, May 17, 2022 at 04:14:49PM -0700, Namhyung Kim escreveu: > On Mon, May 16, 2022 at 6:57 PM Chengdong Li <brytonlee01@gmail.com> wrote: > > Signed-off-by: Chengdong Li <chengdongli@tencent.com> > > Acked-by: Namhyung Kim <namhyung@kernel.org> Thanks, applied. - Arnaldo
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