* [PATCH v4 0/2] arm & arm64: perf: Fix callchain parse error with kernel tracepoint events
@ 2015-05-08 5:43 Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 1/2] arm: " Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 2/2] arm64: " Hou Pengyang
0 siblings, 2 replies; 7+ messages in thread
From: Hou Pengyang @ 2015-05-08 5:43 UTC (permalink / raw)
To: will.deacon, a.p.zijlstra, paulus, acme, mingo
Cc: catalin.marinas, wannan0, linux-kernel, linux-arm-kernel
For arm & arm64, when tracing with tracepoint events, the IP and cpsr
are set to 0, preventing the perf code parsing the callchain and
resolving the symbols correctly.
These two patches fix this by implementing perf_arch_fetch_caller_regs
for arm and arm64, which fills several necessary register info for
callchain unwinding and symbol resolving.
v3->v4:
- fix compile errors
v2->v3:
- split the original patch into two, one for arm and the other arm64;
- change '|=' to '=' when setting cpsr.
Hou Pengyang (2):
arm: perf: Fix callchain parse error with kernel tracepoint events
arm64: perf: Fix callchain parse error with kernel tracepoint events
arch/arm/include/asm/perf_event.h | 7 +++++++
arch/arm64/include/asm/perf_event.h | 7 +++++++
2 files changed, 14 insertions(+)
--
1.8.3.4
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v4 1/2] arm: perf: Fix callchain parse error with kernel tracepoint events
2015-05-08 5:43 [PATCH v4 0/2] arm & arm64: perf: Fix callchain parse error with kernel tracepoint events Hou Pengyang
@ 2015-05-08 5:43 ` Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 2/2] arm64: " Hou Pengyang
1 sibling, 0 replies; 7+ messages in thread
From: Hou Pengyang @ 2015-05-08 5:43 UTC (permalink / raw)
To: will.deacon, a.p.zijlstra, paulus, acme, mingo
Cc: catalin.marinas, wannan0, linux-kernel, linux-arm-kernel
For ARM, when tracing with tracepoint events, the IP and cpsr are set
to 0, preventing the perf code parsing the callchain and resolving the
symbols correctly.
./perf record -e sched:sched_switch -g --call-graph dwarf ls
[ perf record: Captured and wrote 0.006 MB perf.data ]
./perf report -f
Samples: 5 of event 'sched:sched_switch', Event count (approx.): 5
Children Self Command Shared Object Symbol
100.00% 100.00% ls [unknown] [.] 00000000
The fix is to implement perf_arch_fetch_caller_regs for ARM, which fills
several necessary registers used for callchain unwinding, including pc,sp,
fp and cpsr.
With this patch, callchain can be parsed correctly as :
.....
- 100.00% 100.00% ls [kernel.kallsyms] [k] __sched_text_start
+ __sched_text_start
+ 20.00% 0.00% ls libc-2.18.so [.] _dl_addr
+ 20.00% 0.00% ls libc-2.18.so [.] write
.....
Jean Pihet found this in ARM and come up with a patch:
http://thread.gmane.org/gmane.linux.kernel/1734283/focus=1734280
This patch rewrite Jean's patch in C.
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
---
arch/arm/include/asm/perf_event.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm/include/asm/perf_event.h b/arch/arm/include/asm/perf_event.h
index d9cf138..4f9dec4 100644
--- a/arch/arm/include/asm/perf_event.h
+++ b/arch/arm/include/asm/perf_event.h
@@ -19,4 +19,11 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
#endif
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+ (regs)->ARM_pc = (__ip); \
+ (regs)->ARM_fp = (unsigned long) __builtin_frame_address(0); \
+ (regs)->ARM_sp = current_stack_pointer; \
+ (regs)->ARM_cpsr = SVC_MODE; \
+}
+
#endif /* __ARM_PERF_EVENT_H__ */
--
1.8.3.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* [PATCH v4 2/2] arm64: perf: Fix callchain parse error with kernel tracepoint events
2015-05-08 5:43 [PATCH v4 0/2] arm & arm64: perf: Fix callchain parse error with kernel tracepoint events Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 1/2] arm: " Hou Pengyang
@ 2015-05-08 5:43 ` Hou Pengyang
2015-05-08 15:37 ` Will Deacon
1 sibling, 1 reply; 7+ messages in thread
From: Hou Pengyang @ 2015-05-08 5:43 UTC (permalink / raw)
To: will.deacon, a.p.zijlstra, paulus, acme, mingo
Cc: catalin.marinas, wannan0, linux-kernel, linux-arm-kernel
For ARM64, when tracing with tracepoint events, the IP and pstate are set
to 0, preventing the perf code parsing the callchain and resolving the
symbols correctly.
./perf record -e sched:sched_switch -g --call-graph dwarf ls
[ perf record: Captured and wrote 0.146 MB perf.data ]
./perf report -f
Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194
Children Self Command Shared Object Symbol
100.00% 100.00% ls [unknown] [.] 0000000000000000
The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
several necessary registers used for callchain unwinding, including pc,sp,
fp and spsr .
With this patch, callchain can be parsed correctly as follows:
......
+ 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink
+ 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down
+ 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get
+ 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33
- 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify
pfkey_send_policy_notify
pfkey_get
v9fs_vfs_rename
page_follow_link_light
link_path_walk
el0_svc_naked
.......
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
---
arch/arm64/include/asm/perf_event.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index d26d1d5..6471773 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -24,4 +24,11 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
#endif
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+ (regs)->pc = (__ip); \
+ (regs)->regs[AARCH64_INSN_REG_FP] = (unsigned long) __builtin_frame_address(0); \
+ (regs)->sp = current_stack_pointer; \
+ (regs)->pstate = PSR_MODE_EL1h; \
+}
+
#endif
--
1.8.3.4
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v4 2/2] arm64: perf: Fix callchain parse error with kernel tracepoint events
2015-05-08 5:43 ` [PATCH v4 2/2] arm64: " Hou Pengyang
@ 2015-05-08 15:37 ` Will Deacon
2015-05-10 11:07 ` [PATCH v5] " Hou Pengyang
0 siblings, 1 reply; 7+ messages in thread
From: Will Deacon @ 2015-05-08 15:37 UTC (permalink / raw)
To: Hou Pengyang
Cc: a.p.zijlstra, paulus, acme, mingo, Catalin Marinas, wannan0,
linux-kernel, linux-arm-kernel
On Fri, May 08, 2015 at 06:43:04AM +0100, Hou Pengyang wrote:
> For ARM64, when tracing with tracepoint events, the IP and pstate are set
> to 0, preventing the perf code parsing the callchain and resolving the
> symbols correctly.
>
> ./perf record -e sched:sched_switch -g --call-graph dwarf ls
> [ perf record: Captured and wrote 0.146 MB perf.data ]
> ./perf report -f
> Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194
> Children Self Command Shared Object Symbol
> 100.00% 100.00% ls [unknown] [.] 0000000000000000
>
> The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
> several necessary registers used for callchain unwinding, including pc,sp,
> fp and spsr .
>
> With this patch, callchain can be parsed correctly as follows:
>
> ......
> + 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink
> + 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down
> + 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get
> + 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33
> - 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify
> pfkey_send_policy_notify
> pfkey_get
> v9fs_vfs_rename
> page_follow_link_light
> link_path_walk
> el0_svc_naked
> .......
>
> Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
> ---
> arch/arm64/include/asm/perf_event.h | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
> index d26d1d5..6471773 100644
> --- a/arch/arm64/include/asm/perf_event.h
> +++ b/arch/arm64/include/asm/perf_event.h
> @@ -24,4 +24,11 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
> #define perf_misc_flags(regs) perf_misc_flags(regs)
> #endif
>
> +#define perf_arch_fetch_caller_regs(regs, __ip) { \
> + (regs)->pc = (__ip); \
> + (regs)->regs[AARCH64_INSN_REG_FP] = (unsigned long) __builtin_frame_address(0); \
Just a minor thing, but I'd rather we explicitly used '29' as the index
here. The AARCH64_INSN_REG_FP is really for the instruction generation
code used by BPF and I think it's better to be explicit about the register
number here.
Anyway, I've queued your arch/arm/ patch and Catalin can take this one
for 4.2 once you've made the small change above and added my Ack.
Thanks,
Will
^ permalink raw reply [flat|nested] 7+ messages in thread
* [PATCH v5] arm64: perf: Fix callchain parse error with kernel tracepoint events
2015-05-08 15:37 ` Will Deacon
@ 2015-05-10 11:07 ` Hou Pengyang
2015-05-19 16:52 ` Catalin Marinas
0 siblings, 1 reply; 7+ messages in thread
From: Hou Pengyang @ 2015-05-10 11:07 UTC (permalink / raw)
To: will.deacon, catalin.marinas
Cc: a.p.zijlstra, paulus, acme, mingo, wangnan0, linux-arm-kernel,
linux-kernel
For ARM64, when tracing with tracepoint events, the IP and pstate are set
to 0, preventing the perf code parsing the callchain and resolving the
symbols correctly.
./perf record -e sched:sched_switch -g --call-graph dwarf ls
[ perf record: Captured and wrote 0.146 MB perf.data ]
./perf report -f
Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194
Children Self Command Shared Object Symbol
100.00% 100.00% ls [unknown] [.] 0000000000000000
The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
several necessary registers used for callchain unwinding, including pc,sp,
fp and spsr .
With this patch, callchain can be parsed correctly as follows:
......
+ 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink
+ 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down
+ 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get
+ 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33
- 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify
pfkey_send_policy_notify
pfkey_get
v9fs_vfs_rename
page_follow_link_light
link_path_walk
el0_svc_naked
.......
Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
Acked-by: Will Deacon <will.deacon@arm.com>
---
arch/arm64/include/asm/perf_event.h | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
index d26d1d5..6471773 100644
--- a/arch/arm64/include/asm/perf_event.h
+++ b/arch/arm64/include/asm/perf_event.h
@@ -24,4 +24,11 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
#define perf_misc_flags(regs) perf_misc_flags(regs)
#endif
+#define perf_arch_fetch_caller_regs(regs, __ip) { \
+ (regs)->pc = (__ip); \
+ (regs)->regs[29] = (unsigned long) __builtin_frame_address(0); \
+ (regs)->sp = current_stack_pointer; \
+ (regs)->pstate = PSR_MODE_EL1h; \
+}
+
#endif
--
1.8.5.2
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH v5] arm64: perf: Fix callchain parse error with kernel tracepoint events
2015-05-10 11:07 ` [PATCH v5] " Hou Pengyang
@ 2015-05-19 16:52 ` Catalin Marinas
2015-05-20 6:53 ` Jean Pihet
0 siblings, 1 reply; 7+ messages in thread
From: Catalin Marinas @ 2015-05-19 16:52 UTC (permalink / raw)
To: Hou Pengyang
Cc: will.deacon, wangnan0, a.p.zijlstra, linux-kernel, acme, mingo,
paulus, linux-arm-kernel
On Sun, May 10, 2015 at 11:07:40AM +0000, Hou Pengyang wrote:
> For ARM64, when tracing with tracepoint events, the IP and pstate are set
> to 0, preventing the perf code parsing the callchain and resolving the
> symbols correctly.
>
> ./perf record -e sched:sched_switch -g --call-graph dwarf ls
> [ perf record: Captured and wrote 0.146 MB perf.data ]
> ./perf report -f
> Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194
> Children Self Command Shared Object Symbol
> 100.00% 100.00% ls [unknown] [.] 0000000000000000
>
> The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
> several necessary registers used for callchain unwinding, including pc,sp,
> fp and spsr .
>
> With this patch, callchain can be parsed correctly as follows:
>
> ......
> + 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink
> + 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down
> + 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get
> + 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33
> - 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify
> pfkey_send_policy_notify
> pfkey_get
> v9fs_vfs_rename
> page_follow_link_light
> link_path_walk
> el0_svc_naked
> .......
>
> Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
> Acked-by: Will Deacon <will.deacon@arm.com>
Queued for 4.2. Thanks.
--
Catalin
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH v5] arm64: perf: Fix callchain parse error with kernel tracepoint events
2015-05-19 16:52 ` Catalin Marinas
@ 2015-05-20 6:53 ` Jean Pihet
0 siblings, 0 replies; 7+ messages in thread
From: Jean Pihet @ 2015-05-20 6:53 UTC (permalink / raw)
To: Catalin Marinas, Will Deacon
Cc: Hou Pengyang, wangnan0, Peter Zijlstra, LKML, acme, mingo,
Paul Mackerras, linux-arm
Hi Catalin, Will,
On Tue, May 19, 2015 at 6:52 PM, Catalin Marinas
<catalin.marinas@arm.com> wrote:
> On Sun, May 10, 2015 at 11:07:40AM +0000, Hou Pengyang wrote:
>> For ARM64, when tracing with tracepoint events, the IP and pstate are set
>> to 0, preventing the perf code parsing the callchain and resolving the
>> symbols correctly.
>>
>> ./perf record -e sched:sched_switch -g --call-graph dwarf ls
>> [ perf record: Captured and wrote 0.146 MB perf.data ]
>> ./perf report -f
>> Samples: 194 of event 'sched:sched_switch', Event count (approx.): 194
>> Children Self Command Shared Object Symbol
>> 100.00% 100.00% ls [unknown] [.] 0000000000000000
>>
>> The fix is to implement perf_arch_fetch_caller_regs for ARM64, which fills
>> several necessary registers used for callchain unwinding, including pc,sp,
>> fp and spsr .
>>
>> With this patch, callchain can be parsed correctly as follows:
>>
>> ......
>> + 2.63% 0.00% ls [kernel.kallsyms] [k] vfs_symlink
>> + 2.63% 0.00% ls [kernel.kallsyms] [k] follow_down
>> + 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_get
>> + 2.63% 0.00% ls [kernel.kallsyms] [k] do_execveat_common.isra.33
>> - 2.63% 0.00% ls [kernel.kallsyms] [k] pfkey_send_policy_notify
>> pfkey_send_policy_notify
>> pfkey_get
>> v9fs_vfs_rename
>> page_follow_link_light
>> link_path_walk
>> el0_svc_naked
>> .......
>>
>> Signed-off-by: Hou Pengyang <houpengyang@huawei.com>
>> Acked-by: Will Deacon <will.deacon@arm.com>
>
> Queued for 4.2. Thanks.
Nice to see this one going out, finally.
Cheers,
Jean
>
> --
> Catalin
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2015-05-20 6:53 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
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2015-05-08 5:43 [PATCH v4 0/2] arm & arm64: perf: Fix callchain parse error with kernel tracepoint events Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 1/2] arm: " Hou Pengyang
2015-05-08 5:43 ` [PATCH v4 2/2] arm64: " Hou Pengyang
2015-05-08 15:37 ` Will Deacon
2015-05-10 11:07 ` [PATCH v5] " Hou Pengyang
2015-05-19 16:52 ` Catalin Marinas
2015-05-20 6:53 ` Jean Pihet
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