* [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
@ 2019-04-15 15:36 Alexey Budankov
2019-04-17 7:39 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Alexey Budankov @ 2019-04-15 15:36 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Namhyung Kim, Alexander Shishkin, Peter Zijlstra,
Ingo Molnar, Andi Kleen, linux-kernel
When dwarf stacks are collected jointly with user specified register
set using --user-regs option like below the full register context is
still captured on a sample:
$ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.O3
188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002): 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
... FP chain: nr:0
... user regs: mask 0xff0fff ABI 64-bit
.... AX 0x53b
.... BX 0x7ffedbdd3cc0
.... CX 0xffffffff
.... DX 0x33d3a
.... SI 0x7f09b74c38d0
.... DI 0x0
.... BP 0x401260
.... SP 0x7ffedbdd3cc0
.... IP 0x401236
.... FLAGS 0x20a
.... CS 0x33
.... SS 0x2b
.... R8 0x7f09b74c3800
.... R9 0x7f09b74c2da0
.... R10 0xfffffffffffff3ce
.... R11 0x246
.... R12 0x401070
.... R13 0x7ffedbdd5db0
.... R14 0x0
.... R15 0x0
... ustack: size 1024, offset 0xe0
. data_src: 0x5080021
... thread: stack_test2.g.O:23828
...... dso: /root/abudanko/stacks/stack_test2.g.O3
After applying the change suggested in the patch the sample data contain
only user specified register values:
$ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.03
188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002): 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
... FP chain: nr:0
... user regs: mask 0x1c0 ABI 64-bit
.... BP 0x401260
.... SP 0x7ffd3d85cc20
.... IP 0x401236
... ustack: size 1024, offset 0x58
. data_src: 0x5080021
... thread: stack_test2.g.O:23839
...... dso: /root/abudanko/stacks/stack_test2.g.O3
Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
---
tools/perf/util/evsel.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
index 84cfb9fe2fc6..29a223b4c699 100644
--- a/tools/perf/util/evsel.c
+++ b/tools/perf/util/evsel.c
@@ -702,7 +702,8 @@ static void __perf_evsel__config_callchain(struct perf_evsel *evsel,
if (!function) {
perf_evsel__set_sample_bit(evsel, REGS_USER);
perf_evsel__set_sample_bit(evsel, STACK_USER);
- attr->sample_regs_user |= PERF_REGS_MASK;
+ if (!opts->sample_user_regs)
+ attr->sample_regs_user |= PERF_REGS_MASK;
attr->sample_stack_user = param->dump_size;
attr->exclude_callchain_user = 1;
} else {
--
2.20.1
^ permalink raw reply related [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-15 15:36 [PATCH v1] perf record: collect user registers set jointly with dwarf stacks Alexey Budankov
@ 2019-04-17 7:39 ` Jiri Olsa
2019-04-17 14:35 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Olsa @ 2019-04-17 7:39 UTC (permalink / raw)
To: Alexey Budankov
Cc: Arnaldo Carvalho de Melo, Namhyung Kim, Alexander Shishkin,
Peter Zijlstra, Ingo Molnar, Andi Kleen, linux-kernel
On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
>
> When dwarf stacks are collected jointly with user specified register
> set using --user-regs option like below the full register context is
> still captured on a sample:
>
> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.O3
>
> 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002): 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
> ... FP chain: nr:0
> ... user regs: mask 0xff0fff ABI 64-bit
> .... AX 0x53b
> .... BX 0x7ffedbdd3cc0
> .... CX 0xffffffff
> .... DX 0x33d3a
> .... SI 0x7f09b74c38d0
> .... DI 0x0
> .... BP 0x401260
> .... SP 0x7ffedbdd3cc0
> .... IP 0x401236
> .... FLAGS 0x20a
> .... CS 0x33
> .... SS 0x2b
> .... R8 0x7f09b74c3800
> .... R9 0x7f09b74c2da0
> .... R10 0xfffffffffffff3ce
> .... R11 0x246
> .... R12 0x401070
> .... R13 0x7ffedbdd5db0
> .... R14 0x0
> .... R15 0x0
> ... ustack: size 1024, offset 0xe0
> . data_src: 0x5080021
> ... thread: stack_test2.g.O:23828
> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>
> After applying the change suggested in the patch the sample data contain
> only user specified register values:
>
> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.03
>
> 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002): 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
> ... FP chain: nr:0
> ... user regs: mask 0x1c0 ABI 64-bit
> .... BP 0x401260
> .... SP 0x7ffd3d85cc20
> .... IP 0x401236
> ... ustack: size 1024, offset 0x58
> . data_src: 0x5080021
> ... thread: stack_test2.g.O:23839
> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>
> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
> ---
> tools/perf/util/evsel.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 84cfb9fe2fc6..29a223b4c699 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -702,7 +702,8 @@ static void __perf_evsel__config_callchain(struct perf_evsel *evsel,
> if (!function) {
> perf_evsel__set_sample_bit(evsel, REGS_USER);
> perf_evsel__set_sample_bit(evsel, STACK_USER);
> - attr->sample_regs_user |= PERF_REGS_MASK;
> + if (!opts->sample_user_regs)
> + attr->sample_regs_user |= PERF_REGS_MASK;
> attr->sample_stack_user = param->dump_size;
> attr->exclude_callchain_user = 1;
> } else {
> --
> 2.20.1
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 7:39 ` Jiri Olsa
@ 2019-04-17 14:35 ` Arnaldo Carvalho de Melo
2019-04-17 14:40 ` Jiri Olsa
0 siblings, 1 reply; 8+ messages in thread
From: Arnaldo Carvalho de Melo @ 2019-04-17 14:35 UTC (permalink / raw)
To: Jiri Olsa
Cc: Alexey Budankov, Namhyung Kim, Alexander Shishkin,
Peter Zijlstra, Ingo Molnar, Andi Kleen, linux-kernel
Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
> On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
> >
> > When dwarf stacks are collected jointly with user specified register
> > set using --user-regs option like below the full register context is
> > still captured on a sample:
> >
> > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.O3
> >
> > 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002): 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
> > ... FP chain: nr:0
> > ... user regs: mask 0xff0fff ABI 64-bit
> > .... AX 0x53b
> > .... BX 0x7ffedbdd3cc0
> > .... CX 0xffffffff
> > .... DX 0x33d3a
> > .... SI 0x7f09b74c38d0
> > .... DI 0x0
> > .... BP 0x401260
> > .... SP 0x7ffedbdd3cc0
> > .... IP 0x401236
> > .... FLAGS 0x20a
> > .... CS 0x33
> > .... SS 0x2b
> > .... R8 0x7f09b74c3800
> > .... R9 0x7f09b74c2da0
> > .... R10 0xfffffffffffff3ce
> > .... R11 0x246
> > .... R12 0x401070
> > .... R13 0x7ffedbdd5db0
> > .... R14 0x0
> > .... R15 0x0
> > ... ustack: size 1024, offset 0xe0
> > . data_src: 0x5080021
> > ... thread: stack_test2.g.O:23828
> > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> >
> > After applying the change suggested in the patch the sample data contain
> > only user specified register values:
> >
> > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.03
> >
> > 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002): 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
> > ... FP chain: nr:0
> > ... user regs: mask 0x1c0 ABI 64-bit
> > .... BP 0x401260
> > .... SP 0x7ffd3d85cc20
> > .... IP 0x401236
> > ... ustack: size 1024, offset 0x58
> > . data_src: 0x5080021
> > ... thread: stack_test2.g.O:23839
> > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> >
> > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>
> Acked-by: Jiri Olsa <jolsa@kernel.org>
So, there are registers that are needed to do the DWARF unwinding,
right? But at the same time, if the user says only some are needed, he
better know what they're doing and ask for at least the registers needed
for the unwinding process to be successfull, right?
- Arnaldo
> thanks,
> jirka
>
> > ---
> > tools/perf/util/evsel.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > index 84cfb9fe2fc6..29a223b4c699 100644
> > --- a/tools/perf/util/evsel.c
> > +++ b/tools/perf/util/evsel.c
> > @@ -702,7 +702,8 @@ static void __perf_evsel__config_callchain(struct perf_evsel *evsel,
> > if (!function) {
> > perf_evsel__set_sample_bit(evsel, REGS_USER);
> > perf_evsel__set_sample_bit(evsel, STACK_USER);
> > - attr->sample_regs_user |= PERF_REGS_MASK;
> > + if (!opts->sample_user_regs)
> > + attr->sample_regs_user |= PERF_REGS_MASK;
> > attr->sample_stack_user = param->dump_size;
> > attr->exclude_callchain_user = 1;
> > } else {
> > --
> > 2.20.1
> >
--
- Arnaldo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 14:35 ` Arnaldo Carvalho de Melo
@ 2019-04-17 14:40 ` Jiri Olsa
2019-04-17 15:48 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 8+ messages in thread
From: Jiri Olsa @ 2019-04-17 14:40 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Alexey Budankov, Namhyung Kim, Alexander Shishkin,
Peter Zijlstra, Ingo Molnar, Andi Kleen, linux-kernel
On Wed, Apr 17, 2019 at 11:35:42AM -0300, Arnaldo Carvalho de Melo wrote:
> Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
> > On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
> > >
> > > When dwarf stacks are collected jointly with user specified register
> > > set using --user-regs option like below the full register context is
> > > still captured on a sample:
> > >
> > > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.O3
> > >
> > > 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002): 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
> > > ... FP chain: nr:0
> > > ... user regs: mask 0xff0fff ABI 64-bit
> > > .... AX 0x53b
> > > .... BX 0x7ffedbdd3cc0
> > > .... CX 0xffffffff
> > > .... DX 0x33d3a
> > > .... SI 0x7f09b74c38d0
> > > .... DI 0x0
> > > .... BP 0x401260
> > > .... SP 0x7ffedbdd3cc0
> > > .... IP 0x401236
> > > .... FLAGS 0x20a
> > > .... CS 0x33
> > > .... SS 0x2b
> > > .... R8 0x7f09b74c3800
> > > .... R9 0x7f09b74c2da0
> > > .... R10 0xfffffffffffff3ce
> > > .... R11 0x246
> > > .... R12 0x401070
> > > .... R13 0x7ffedbdd5db0
> > > .... R14 0x0
> > > .... R15 0x0
> > > ... ustack: size 1024, offset 0xe0
> > > . data_src: 0x5080021
> > > ... thread: stack_test2.g.O:23828
> > > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> > >
> > > After applying the change suggested in the patch the sample data contain
> > > only user specified register values:
> > >
> > > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- matrix.gcc.g.03
> > >
> > > 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002): 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
> > > ... FP chain: nr:0
> > > ... user regs: mask 0x1c0 ABI 64-bit
> > > .... BP 0x401260
> > > .... SP 0x7ffd3d85cc20
> > > .... IP 0x401236
> > > ... ustack: size 1024, offset 0x58
> > > . data_src: 0x5080021
> > > ... thread: stack_test2.g.O:23839
> > > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> > >
> > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> >
> > Acked-by: Jiri Olsa <jolsa@kernel.org>
>
> So, there are registers that are needed to do the DWARF unwinding,
> right? But at the same time, if the user says only some are needed, he
> better know what they're doing and ask for at least the registers needed
> for the unwinding process to be successfull, right?
yep, that's how understand that
jirka
>
> - Arnaldo
>
> > thanks,
> > jirka
> >
> > > ---
> > > tools/perf/util/evsel.c | 3 ++-
> > > 1 file changed, 2 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> > > index 84cfb9fe2fc6..29a223b4c699 100644
> > > --- a/tools/perf/util/evsel.c
> > > +++ b/tools/perf/util/evsel.c
> > > @@ -702,7 +702,8 @@ static void __perf_evsel__config_callchain(struct perf_evsel *evsel,
> > > if (!function) {
> > > perf_evsel__set_sample_bit(evsel, REGS_USER);
> > > perf_evsel__set_sample_bit(evsel, STACK_USER);
> > > - attr->sample_regs_user |= PERF_REGS_MASK;
> > > + if (!opts->sample_user_regs)
> > > + attr->sample_regs_user |= PERF_REGS_MASK;
> > > attr->sample_stack_user = param->dump_size;
> > > attr->exclude_callchain_user = 1;
> > > } else {
> > > --
> > > 2.20.1
> > >
>
> --
>
> - Arnaldo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 14:40 ` Jiri Olsa
@ 2019-04-17 15:48 ` Arnaldo Carvalho de Melo
2019-04-17 17:45 ` Alexey Budankov
0 siblings, 1 reply; 8+ messages in thread
From: Arnaldo Carvalho de Melo @ 2019-04-17 15:48 UTC (permalink / raw)
To: Jiri Olsa, Arnaldo Carvalho de Melo
Cc: Alexey Budankov, Namhyung Kim, Alexander Shishkin,
Peter Zijlstra, Ingo Molnar, Andi Kleen, linux-kernel
On April 17, 2019 11:40:02 AM GMT-03:00, Jiri Olsa <jolsa@redhat.com> wrote:
>On Wed, Apr 17, 2019 at 11:35:42AM -0300, Arnaldo Carvalho de Melo
>wrote:
>> Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
>> > On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
>> > >
>> > > When dwarf stacks are collected jointly with user specified
>register
>> > > set using --user-regs option like below the full register context
>is
>> > > still captured on a sample:
>> > >
>> > > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>-- matrix.gcc.g.O3
>> > >
>> > > 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002):
>23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
>> > > ... FP chain: nr:0
>> > > ... user regs: mask 0xff0fff ABI 64-bit
>> > > .... AX 0x53b
>> > > .... BX 0x7ffedbdd3cc0
>> > > .... CX 0xffffffff
>> > > .... DX 0x33d3a
>> > > .... SI 0x7f09b74c38d0
>> > > .... DI 0x0
>> > > .... BP 0x401260
>> > > .... SP 0x7ffedbdd3cc0
>> > > .... IP 0x401236
>> > > .... FLAGS 0x20a
>> > > .... CS 0x33
>> > > .... SS 0x2b
>> > > .... R8 0x7f09b74c3800
>> > > .... R9 0x7f09b74c2da0
>> > > .... R10 0xfffffffffffff3ce
>> > > .... R11 0x246
>> > > .... R12 0x401070
>> > > .... R13 0x7ffedbdd5db0
>> > > .... R14 0x0
>> > > .... R15 0x0
>> > > ... ustack: size 1024, offset 0xe0
>> > > . data_src: 0x5080021
>> > > ... thread: stack_test2.g.O:23828
>> > > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>> > >
>> > > After applying the change suggested in the patch the sample data
>contain
>> > > only user specified register values:
>> > >
>> > > $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>-- matrix.gcc.g.03
>> > >
>> > > 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002):
>23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
>> > > ... FP chain: nr:0
>> > > ... user regs: mask 0x1c0 ABI 64-bit
>> > > .... BP 0x401260
>> > > .... SP 0x7ffd3d85cc20
>> > > .... IP 0x401236
>> > > ... ustack: size 1024, offset 0x58
>> > > . data_src: 0x5080021
>> > > ... thread: stack_test2.g.O:23839
>> > > ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>> > >
>> > > Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>> >
>> > Acked-by: Jiri Olsa <jolsa@kernel.org>
>>
>> So, there are registers that are needed to do the DWARF unwinding,
>> right? But at the same time, if the user says only some are needed,
>he
>> better know what they're doing and ask for at least the registers
>needed
>> for the unwinding process to be successfull, right?
>
>yep, that's how understand that
So we need to document that, stating that specifying a set of registers together with requesting DWARF callchains may break things.
- Arnaldo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 15:48 ` Arnaldo Carvalho de Melo
@ 2019-04-17 17:45 ` Alexey Budankov
2019-04-17 18:47 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 8+ messages in thread
From: Alexey Budankov @ 2019-04-17 17:45 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo, Jiri Olsa
Cc: Namhyung Kim, Alexander Shishkin, Peter Zijlstra, Ingo Molnar,
Andi Kleen, linux-kernel
Hi Arnaldo,
On 17.04.2019 18:48, Arnaldo Carvalho de Melo wrote:
> On April 17, 2019 11:40:02 AM GMT-03:00, Jiri Olsa <jolsa@redhat.com> wrote:
>> On Wed, Apr 17, 2019 at 11:35:42AM -0300, Arnaldo Carvalho de Melo
>> wrote:
>>> Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
>>>> On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
>>>>>
>>>>> When dwarf stacks are collected jointly with user specified
>> register
>>>>> set using --user-regs option like below the full register context
>> is
>>>>> still captured on a sample:
>>>>>
>>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>> -- matrix.gcc.g.O3
>>>>>
>>>>> 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002):
>> 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
>>>>> ... FP chain: nr:0
>>>>> ... user regs: mask 0xff0fff ABI 64-bit
>>>>> .... AX 0x53b
>>>>> .... BX 0x7ffedbdd3cc0
>>>>> .... CX 0xffffffff
>>>>> .... DX 0x33d3a
>>>>> .... SI 0x7f09b74c38d0
>>>>> .... DI 0x0
>>>>> .... BP 0x401260
>>>>> .... SP 0x7ffedbdd3cc0
>>>>> .... IP 0x401236
>>>>> .... FLAGS 0x20a
>>>>> .... CS 0x33
>>>>> .... SS 0x2b
>>>>> .... R8 0x7f09b74c3800
>>>>> .... R9 0x7f09b74c2da0
>>>>> .... R10 0xfffffffffffff3ce
>>>>> .... R11 0x246
>>>>> .... R12 0x401070
>>>>> .... R13 0x7ffedbdd5db0
>>>>> .... R14 0x0
>>>>> .... R15 0x0
>>>>> ... ustack: size 1024, offset 0xe0
>>>>> . data_src: 0x5080021
>>>>> ... thread: stack_test2.g.O:23828
>>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>>>>>
>>>>> After applying the change suggested in the patch the sample data
>> contain
>>>>> only user specified register values:
>>>>>
>>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>> -- matrix.gcc.g.03
>>>>>
>>>>> 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002):
>> 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
>>>>> ... FP chain: nr:0
>>>>> ... user regs: mask 0x1c0 ABI 64-bit
>>>>> .... BP 0x401260
>>>>> .... SP 0x7ffd3d85cc20
>>>>> .... IP 0x401236
>>>>> ... ustack: size 1024, offset 0x58
>>>>> . data_src: 0x5080021
>>>>> ... thread: stack_test2.g.O:23839
>>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>>>>>
>>>>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>>>>
>>>> Acked-by: Jiri Olsa <jolsa@kernel.org>
>>>
>>> So, there are registers that are needed to do the DWARF unwinding,
>>> right? But at the same time, if the user says only some are needed,
>> he
>>> better know what they're doing and ask for at least the registers
>> needed
>>> for the unwinding process to be successfull, right?
>>
>> yep, that's how understand that
>
> So we need to document that, stating that specifying a set of registers together with requesting DWARF callchains may break things.
Do you mean break callchains if omitting IP,SP,BP?
For example like this:
$ perf record -g --call-graph dwarf,1024 --user-regs=AX,BX,CX -- matrix.gcc.g.O3
~Alexey
>
> - Arnaldo
>
>
>
>
>
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 17:45 ` Alexey Budankov
@ 2019-04-17 18:47 ` Arnaldo Carvalho de Melo
2019-04-18 9:01 ` Alexey Budankov
0 siblings, 1 reply; 8+ messages in thread
From: Arnaldo Carvalho de Melo @ 2019-04-17 18:47 UTC (permalink / raw)
To: Alexey Budankov
Cc: Arnaldo Carvalho de Melo, Jiri Olsa, Namhyung Kim,
Alexander Shishkin, Peter Zijlstra, Ingo Molnar, Andi Kleen,
linux-kernel
Em Wed, Apr 17, 2019 at 08:45:08PM +0300, Alexey Budankov escreveu:
> Hi Arnaldo,
>
> On 17.04.2019 18:48, Arnaldo Carvalho de Melo wrote:
> > On April 17, 2019 11:40:02 AM GMT-03:00, Jiri Olsa <jolsa@redhat.com> wrote:
> >> On Wed, Apr 17, 2019 at 11:35:42AM -0300, Arnaldo Carvalho de Melo
> >> wrote:
> >>> Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
> >>>> On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
> >>>>>
> >>>>> When dwarf stacks are collected jointly with user specified
> >> register
> >>>>> set using --user-regs option like below the full register context
> >> is
> >>>>> still captured on a sample:
> >>>>>
> >>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
> >> -- matrix.gcc.g.O3
> >>>>>
> >>>>> 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002):
> >> 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
> >>>>> ... FP chain: nr:0
> >>>>> ... user regs: mask 0xff0fff ABI 64-bit
> >>>>> .... AX 0x53b
> >>>>> .... BX 0x7ffedbdd3cc0
> >>>>> .... CX 0xffffffff
> >>>>> .... DX 0x33d3a
> >>>>> .... SI 0x7f09b74c38d0
> >>>>> .... DI 0x0
> >>>>> .... BP 0x401260
> >>>>> .... SP 0x7ffedbdd3cc0
> >>>>> .... IP 0x401236
> >>>>> .... FLAGS 0x20a
> >>>>> .... CS 0x33
> >>>>> .... SS 0x2b
> >>>>> .... R8 0x7f09b74c3800
> >>>>> .... R9 0x7f09b74c2da0
> >>>>> .... R10 0xfffffffffffff3ce
> >>>>> .... R11 0x246
> >>>>> .... R12 0x401070
> >>>>> .... R13 0x7ffedbdd5db0
> >>>>> .... R14 0x0
> >>>>> .... R15 0x0
> >>>>> ... ustack: size 1024, offset 0xe0
> >>>>> . data_src: 0x5080021
> >>>>> ... thread: stack_test2.g.O:23828
> >>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> >>>>>
> >>>>> After applying the change suggested in the patch the sample data
> >> contain
> >>>>> only user specified register values:
> >>>>>
> >>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
> >> -- matrix.gcc.g.03
> >>>>>
> >>>>> 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002):
> >> 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
> >>>>> ... FP chain: nr:0
> >>>>> ... user regs: mask 0x1c0 ABI 64-bit
> >>>>> .... BP 0x401260
> >>>>> .... SP 0x7ffd3d85cc20
> >>>>> .... IP 0x401236
> >>>>> ... ustack: size 1024, offset 0x58
> >>>>> . data_src: 0x5080021
> >>>>> ... thread: stack_test2.g.O:23839
> >>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
> >>>>>
> >>>>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
> >>>>
> >>>> Acked-by: Jiri Olsa <jolsa@kernel.org>
> >>>
> >>> So, there are registers that are needed to do the DWARF unwinding,
> >>> right? But at the same time, if the user says only some are needed,
> >> he
> >>> better know what they're doing and ask for at least the registers
> >> needed
> >>> for the unwinding process to be successfull, right?
> >>
> >> yep, that's how understand that
> >
> > So we need to document that, stating that specifying a set of registers together with requesting DWARF callchains may break things.
>
> Do you mean break callchains if omitting IP,SP,BP?
> For example like this:
> $ perf record -g --call-graph dwarf,1024 --user-regs=AX,BX,CX -- matrix.gcc.g.O3
Right, i.e. if you don't use --user-regs, then a set of registers will
be asked for by --call-graph dwarf, right? If you use both and specify a
subset that doesn't have some of the asked for --call-graph dwarf, what
happens?
- Arnaldo
^ permalink raw reply [flat|nested] 8+ messages in thread
* Re: [PATCH v1] perf record: collect user registers set jointly with dwarf stacks
2019-04-17 18:47 ` Arnaldo Carvalho de Melo
@ 2019-04-18 9:01 ` Alexey Budankov
0 siblings, 0 replies; 8+ messages in thread
From: Alexey Budankov @ 2019-04-18 9:01 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Jiri Olsa, Namhyung Kim, Alexander Shishkin, Peter Zijlstra,
Ingo Molnar, Andi Kleen, linux-kernel
On 17.04.2019 21:47, Arnaldo Carvalho de Melo wrote:
> Em Wed, Apr 17, 2019 at 08:45:08PM +0300, Alexey Budankov escreveu:
>> Hi Arnaldo,
>>
>> On 17.04.2019 18:48, Arnaldo Carvalho de Melo wrote:
>>> On April 17, 2019 11:40:02 AM GMT-03:00, Jiri Olsa <jolsa@redhat.com> wrote:
>>>> On Wed, Apr 17, 2019 at 11:35:42AM -0300, Arnaldo Carvalho de Melo
>>>> wrote:
>>>>> Em Wed, Apr 17, 2019 at 09:39:52AM +0200, Jiri Olsa escreveu:
>>>>>> On Mon, Apr 15, 2019 at 06:36:13PM +0300, Alexey Budankov wrote:
>>>>>>>
>>>>>>> When dwarf stacks are collected jointly with user specified
>>>> register
>>>>>>> set using --user-regs option like below the full register context
>>>> is
>>>>>>> still captured on a sample:
>>>>>>>
>>>>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>>>> -- matrix.gcc.g.O3
>>>>>>>
>>>>>>> 188143843893585 0x6b48 [0x4f8]: PERF_RECORD_SAMPLE(IP, 0x4002):
>>>> 23828/23828: 0x401236 period: 1363819 addr: 0x7ffedbdd51ac
>>>>>>> ... FP chain: nr:0
>>>>>>> ... user regs: mask 0xff0fff ABI 64-bit
>>>>>>> .... AX 0x53b
>>>>>>> .... BX 0x7ffedbdd3cc0
>>>>>>> .... CX 0xffffffff
>>>>>>> .... DX 0x33d3a
>>>>>>> .... SI 0x7f09b74c38d0
>>>>>>> .... DI 0x0
>>>>>>> .... BP 0x401260
>>>>>>> .... SP 0x7ffedbdd3cc0
>>>>>>> .... IP 0x401236
>>>>>>> .... FLAGS 0x20a
>>>>>>> .... CS 0x33
>>>>>>> .... SS 0x2b
>>>>>>> .... R8 0x7f09b74c3800
>>>>>>> .... R9 0x7f09b74c2da0
>>>>>>> .... R10 0xfffffffffffff3ce
>>>>>>> .... R11 0x246
>>>>>>> .... R12 0x401070
>>>>>>> .... R13 0x7ffedbdd5db0
>>>>>>> .... R14 0x0
>>>>>>> .... R15 0x0
>>>>>>> ... ustack: size 1024, offset 0xe0
>>>>>>> . data_src: 0x5080021
>>>>>>> ... thread: stack_test2.g.O:23828
>>>>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>>>>>>>
>>>>>>> After applying the change suggested in the patch the sample data
>>>> contain
>>>>>>> only user specified register values:
>>>>>>>
>>>>>>> $ perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP
>>>> -- matrix.gcc.g.03
>>>>>>>
>>>>>>> 188368474305373 0x5e40 [0x470]: PERF_RECORD_SAMPLE(IP, 0x4002):
>>>> 23839/23839: 0x401236 period: 1260507 addr: 0x7ffd3d85e96c
>>>>>>> ... FP chain: nr:0
>>>>>>> ... user regs: mask 0x1c0 ABI 64-bit
>>>>>>> .... BP 0x401260
>>>>>>> .... SP 0x7ffd3d85cc20
>>>>>>> .... IP 0x401236
>>>>>>> ... ustack: size 1024, offset 0x58
>>>>>>> . data_src: 0x5080021
>>>>>>> ... thread: stack_test2.g.O:23839
>>>>>>> ...... dso: /root/abudanko/stacks/stack_test2.g.O3
>>>>>>>
>>>>>>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>>>>>>
>>>>>> Acked-by: Jiri Olsa <jolsa@kernel.org>
>>>>>
>>>>> So, there are registers that are needed to do the DWARF unwinding,
>>>>> right? But at the same time, if the user says only some are needed,
>>>> he
>>>>> better know what they're doing and ask for at least the registers
>>>> needed
>>>>> for the unwinding process to be successfull, right?
>>>>
>>>> yep, that's how understand that
>>>
>>> So we need to document that, stating that specifying a set of registers together with requesting DWARF callchains may break things.
>>
>> Do you mean break callchains if omitting IP,SP,BP?
>> For example like this:
>> $ perf record -g --call-graph dwarf,1024 --user-regs=AX,BX,CX -- matrix.gcc.g.O3
>
> Right, i.e. if you don't use --user-regs, then a set of registers will
> be asked for by --call-graph dwarf, right? If you use both and specify a
Right. Full register set is collected.
> subset that doesn't have some of the asked for --call-graph dwarf, what
> happens?
It reports corrupted trace:
./perf record -g --call-graph dwarf,1024 --user-regs=IP -- ./stack_test2.2048.g.O3
in foo() ...
in bar() ...
done
[ perf record: Woken up 254 times to write data ]
[ perf record: Captured and wrote 63.341 MB perf.data (59286 samples) ]
[root@nntvtune39 stacks]# ./perf report -D > log.txt
unwind: can't read reg 7
0x835c0 [0x8]: failed to process type: 68
Error:
failed to process sample
./perf record -g --call-graph dwarf,1024 --user-regs=SP -- ./stack_test2.2048.g.O3
in foo() ...
in bar() ...
done
[ perf record: Woken up 256 times to write data ]
[ perf record: Captured and wrote 63.863 MB perf.data (59773 samples) ]
[root@nntvtune39 stacks]# ./perf report -D > log.txt
0x83180 [0x8]: failed to process type: 68
Error:
failed to process sample
./perf record -g --call-graph dwarf,1024 --user-regs=IP,SP -- ./stack_test2.2048.g.O3
in foo() ...
in bar() ...
done
[ perf record: Woken up 258 times to write data ]
[ perf record: Captured and wrote 64.301 MB perf.data (59757 samples) ]
[root@nntvtune39 stacks]# ./perf report -D > log.txt
unwind: can't read reg 6
./perf record -g --call-graph dwarf,1024 --user-regs=IP,SP,BP -- ./stack_test2.2048.g.O3
in foo() ...
in bar() ...
done
[ perf record: Woken up 259 times to write data ]
[ perf record: Captured and wrote 64.737 MB perf.data (59739 samples) ]
[root@nntvtune39 stacks]# ./perf report -D > log.txt
It looks like some dwarf set IP,SP,BP has to be collected anyways
and the set has to be consolidated with the registers specified
using --user-regs option:
-g call-graph dwarf,K all_regs
-g call-graph dwarf,K --user-regs=user_regs dwarf_regs | user_regs
--user-regs=user_regs user_regs
~Alexey
>
> - Arnaldo
>
^ permalink raw reply [flat|nested] 8+ messages in thread
end of thread, other threads:[~2019-04-18 9:01 UTC | newest]
Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-04-15 15:36 [PATCH v1] perf record: collect user registers set jointly with dwarf stacks Alexey Budankov
2019-04-17 7:39 ` Jiri Olsa
2019-04-17 14:35 ` Arnaldo Carvalho de Melo
2019-04-17 14:40 ` Jiri Olsa
2019-04-17 15:48 ` Arnaldo Carvalho de Melo
2019-04-17 17:45 ` Alexey Budankov
2019-04-17 18:47 ` Arnaldo Carvalho de Melo
2019-04-18 9:01 ` Alexey Budankov
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