Re: [PATCH] powerpc/book3s32: Only select PPC_HAVE_PMU on e600

From: Michael Ellerman
Date: Thu Sep 03 2015 - 05:47:37 EST


On Thu, 2015-09-03 at 11:27 +0200, Christophe Leroy wrote:
> On PPC832x, perf record/report reports martian addresses
>
> 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
> [.....]
>
> This is due to function perf_instruction_pointer() reading SPR SIAR
> which doesn't exist on e300 core. The perf_instruction_pointer() is
> redefined in arch/powerpc/perf/core-book3s.c when CONFIG_PPC_PERF_CTRS
> is selected.
>
> This patch moves the selection of CONFIG_PPC_HAVE_PMU in 86xx section
> so that CONFIG_PPC_PERF_CTRS won't be selected for other 6xx powerpc

I don't know much about these old 6xx cpus, deferring to Paul.

cheers


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