* Strange reports of perf events on powerpc 83xx
@ 2015-08-27 13:58 leroy christophe
2015-09-02 14:20 ` Joakim Tjernlund
0 siblings, 1 reply; 3+ messages in thread
From: leroy christophe @ 2015-08-27 13:58 UTC (permalink / raw)
To: LinuxPPC-dev, linux-kernel@vger.kernel.org
Hi,
Has anybody already used 'perf' tool on powerpc MPC83xx ?
I have been succesfully using perf on MPC8xx, but on MPC83xx I get
something strange.
perf record/report reports addresses on user stack, as if it was mixing
up D accesses and I accesses.
Any idea of what the problem can be ?
# Samples: 8K of event 'cpu-clock'
# Event count (approx.): 2196000000
#
# Overhead Command Shared Object Symbol
# ........ ............ ..................
............................................
#
2.62% perf_reseau4 libpthread-2.18.so [.] __libc_send
2.56% perf_reseau4 [kernel.kallsyms] [k] __ip_make_skb
1.62% perf_reseau4 [kernel.kallsyms] [k] __ip_append_data.isra.39
1.55% perf_reseau4 [kernel.kallsyms] [k] ip_finish_output
1.33% perf_reseau4 [unknown] [k] 0x7ffffd94
1.33% perf_reseau4 [unknown] [k] 0x7ffffd95
1.28% perf_reseau4 [unknown] [k] 0x7ffffd97
1.26% perf_reseau4 [unknown] [k] 0x7ffffda3
1.24% perf_reseau4 [unknown] [k] 0x7ffffd98
1.22% perf_reseau4 [unknown] [k] 0x7ffffd92
1.22% perf_reseau4 [unknown] [k] 0x7ffffd9b
1.22% perf_reseau4 [unknown] [k] 0x7ffffdaa
1.21% perf_reseau4 [unknown] [k] 0x7ffffd96
1.18% perf_reseau4 [unknown] [k] 0x7ffffda7
1.17% perf_reseau4 [unknown] [k] 0x7ffffd8d
1.17% perf_reseau4 [unknown] [k] 0x7ffffd99
1.13% perf_reseau4 [unknown] [k] 0x7ffffd90
1.13% perf_reseau4 [unknown] [k] 0x7ffffda2
1.12% perf_reseau4 [kernel.kallsyms] [k] __local_bh_enable_ip
1.12% perf_reseau4 [unknown] [k] 0x7ffffd9c
1.12% perf_reseau4 [unknown] [k] 0x7ffffd9e
1.10% perf_reseau4 [unknown] [k] 0x7ffffda0
1.08% perf_reseau4 [unknown] [k] 0x7ffffd9f
1.08% perf_reseau4 [unknown] [k] 0x7ffffda6
1.05% perf_reseau4 [unknown] [k] 0x7ffffda8
1.02% perf_reseau4 [unknown] [k] 0x7ffffd9a
1.01% perf_reseau4 [unknown] [k] 0x7ffffdb0
1.00% perf_reseau4 [unknown] [k] 0x7ffffd89
1.00% perf_reseau4 [unknown] [k] 0x7ffffd8b
1.00% perf_reseau4 [unknown] [k] 0x7ffffdac
Christophe
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: Strange reports of perf events on powerpc 83xx
2015-08-27 13:58 Strange reports of perf events on powerpc 83xx leroy christophe
@ 2015-09-02 14:20 ` Joakim Tjernlund
2015-09-02 18:48 ` christophe leroy
0 siblings, 1 reply; 3+ messages in thread
From: Joakim Tjernlund @ 2015-09-02 14:20 UTC (permalink / raw)
To: christophe.leroy@c-s.fr, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org
On Thu, 2015-08-27 at 15:58 +0200, leroy christophe wrote:
> Hi,
>=20
> Has anybody already used 'perf' tool on powerpc MPC83xx ?
>=20
> I have been succesfully using perf on MPC8xx, but on MPC83xx I get=20
> something strange.
>=20
> perf record/report reports addresses on user stack, as if it was mixing=20
> up D accesses and I accesses.
>=20
> Any idea of what the problem can be ?
We are also experiencing strange addresses on 83xx, did find the cause
of this problem?
We are using Linux 4.1.0
>=20
> # Samples: 8K of event 'cpu-clock'
> # Event count (approx.): 2196000000
> #
> # Overhead Command Shared Object Symbol
> # ........ ............ ..................=20
> ............................................
> #
> 2.62% perf_reseau4 libpthread-2.18.so [.] __libc_send
> 2.56% perf_reseau4 [kernel.kallsyms] [k] __ip_make_skb
> 1.62% perf_reseau4 [kernel.kallsyms] [k] __ip_append_data.isra.=
39
> 1.55% perf_reseau4 [kernel.kallsyms] [k] ip_finish_output
> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd94
> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd95
> 1.28% perf_reseau4 [unknown] [k] 0x7ffffd97
> 1.26% perf_reseau4 [unknown] [k] 0x7ffffda3
> 1.24% perf_reseau4 [unknown] [k] 0x7ffffd98
> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd92
> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd9b
> 1.22% perf_reseau4 [unknown] [k] 0x7ffffdaa
> 1.21% perf_reseau4 [unknown] [k] 0x7ffffd96
> 1.18% perf_reseau4 [unknown] [k] 0x7ffffda7
> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd8d
> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd99
> 1.13% perf_reseau4 [unknown] [k] 0x7ffffd90
> 1.13% perf_reseau4 [unknown] [k] 0x7ffffda2
> 1.12% perf_reseau4 [kernel.kallsyms] [k] __local_bh_enable_ip
> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9c
> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9e
> 1.10% perf_reseau4 [unknown] [k] 0x7ffffda0
> 1.08% perf_reseau4 [unknown] [k] 0x7ffffd9f
> 1.08% perf_reseau4 [unknown] [k] 0x7ffffda6
> 1.05% perf_reseau4 [unknown] [k] 0x7ffffda8
> 1.02% perf_reseau4 [unknown] [k] 0x7ffffd9a
> 1.01% perf_reseau4 [unknown] [k] 0x7ffffdb0
> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd89
> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd8b
> 1.00% perf_reseau4 [unknown] [k] 0x7ffffdac
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Strange reports of perf events on powerpc 83xx
2015-09-02 14:20 ` Joakim Tjernlund
@ 2015-09-02 18:48 ` christophe leroy
0 siblings, 0 replies; 3+ messages in thread
From: christophe leroy @ 2015-09-02 18:48 UTC (permalink / raw)
To: Joakim Tjernlund, linuxppc-dev@lists.ozlabs.org,
linux-kernel@vger.kernel.org, Paul Mackerras, Anton Blanchard,
sukadev@linux.vnet.ibm.com
Le 02/09/2015 16:20, Joakim Tjernlund a écrit :
> On Thu, 2015-08-27 at 15:58 +0200, leroy christophe wrote:
>> Hi,
>>
>> Has anybody already used 'perf' tool on powerpc MPC83xx ?
>>
>> I have been succesfully using perf on MPC8xx, but on MPC83xx I get
>> something strange.
>>
>> perf record/report reports addresses on user stack, as if it was mixing
>> up D accesses and I accesses.
>>
>> Any idea of what the problem can be ?
> We are also experiencing strange addresses on 83xx, did find the cause
> of this problem?
>
> We are using Linux 4.1.0
I identified this afternoon that the issue comes from
perf_instruction_pointer()
which reads SPRN_SIAR instead of using the NIP register from the pt_regs
struct
According to the MPC8323 reference manual, there is no such register.
I'm looking at the history in order to fully understand the reason.
Looks like PPC_HAVE_PMU_SUPPORT is selected for all PPC_BOOK3S_32 allthought
mpc832x has no PMU.
Christophe
>
>> # Samples: 8K of event 'cpu-clock'
>> # Event count (approx.): 2196000000
>> #
>> # Overhead Command Shared Object Symbol
>> # ........ ............ ..................
>> ............................................
>> #
>> 2.62% perf_reseau4 libpthread-2.18.so [.] __libc_send
>> 2.56% perf_reseau4 [kernel.kallsyms] [k] __ip_make_skb
>> 1.62% perf_reseau4 [kernel.kallsyms] [k] __ip_append_data.isra.39
>> 1.55% perf_reseau4 [kernel.kallsyms] [k] ip_finish_output
>> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd94
>> 1.33% perf_reseau4 [unknown] [k] 0x7ffffd95
>> 1.28% perf_reseau4 [unknown] [k] 0x7ffffd97
>> 1.26% perf_reseau4 [unknown] [k] 0x7ffffda3
>> 1.24% perf_reseau4 [unknown] [k] 0x7ffffd98
>> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd92
>> 1.22% perf_reseau4 [unknown] [k] 0x7ffffd9b
>> 1.22% perf_reseau4 [unknown] [k] 0x7ffffdaa
>> 1.21% perf_reseau4 [unknown] [k] 0x7ffffd96
>> 1.18% perf_reseau4 [unknown] [k] 0x7ffffda7
>> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd8d
>> 1.17% perf_reseau4 [unknown] [k] 0x7ffffd99
>> 1.13% perf_reseau4 [unknown] [k] 0x7ffffd90
>> 1.13% perf_reseau4 [unknown] [k] 0x7ffffda2
>> 1.12% perf_reseau4 [kernel.kallsyms] [k] __local_bh_enable_ip
>> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9c
>> 1.12% perf_reseau4 [unknown] [k] 0x7ffffd9e
>> 1.10% perf_reseau4 [unknown] [k] 0x7ffffda0
>> 1.08% perf_reseau4 [unknown] [k] 0x7ffffd9f
>> 1.08% perf_reseau4 [unknown] [k] 0x7ffffda6
>> 1.05% perf_reseau4 [unknown] [k] 0x7ffffda8
>> 1.02% perf_reseau4 [unknown] [k] 0x7ffffd9a
>> 1.01% perf_reseau4 [unknown] [k] 0x7ffffdb0
>> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd89
>> 1.00% perf_reseau4 [unknown] [k] 0x7ffffd8b
>> 1.00% perf_reseau4 [unknown] [k] 0x7ffffdac
---
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^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-09-02 14:20 ` Joakim Tjernlund
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