From: Jean Pihet <jean.pihet@newoldbits.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>
Cc: Hou Pengyang <houpengyang@huawei.com>,
wangnan0@huawei.com, Peter Zijlstra <a.p.zijlstra@chello.nl>,
LKML <linux-kernel@vger.kernel.org>,
acme@kernel.org, mingo@redhat.com,
Paul Mackerras <paulus@samba.org>,
linux-arm <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v5] arm64: perf: Fix callchain parse error with kernel tracepoint events
Date: Wed, 20 May 2015 08:53:07 +0200 [thread overview]
Message-ID: <CAORVsuVtHO49Ybu9SNv0XZS6CvvyMV5uQQAxJktOr5+VS-VJvg@mail.gmail.com> (raw)
In-Reply-To: <20150519165202.GA21251@e104818-lin.cambridge.arm.com>
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
prev parent reply other threads:[~2015-05-20 6:53 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
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 [this message]
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