From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Christophe Leroy <christophe.leroy@c-s.fr>
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] perf tools: allow overriding MAX_NR_CPUS at compile time
Date: Thu, 3 May 2018 10:40:37 -0300 [thread overview]
Message-ID: <20180503134037.GB8442@kernel.org> (raw)
In-Reply-To: <20170922112043.8349468C57@po15668-vm-win7.idsi0.si.c-s.fr>
Em Fri, Sep 22, 2017 at 01:20:43PM +0200, Christophe Leroy escreveu:
> After update of kernel, perf tool doesn't run anymore on my
> 32MB RAM powerpc board, but still runs on a 128MB RAM board:
Cleaning up my inbox, found this one, simple enough, still applies,
applied.
These all needs to be dynamicly allocated, but still, with this one can
get a functioning tool, apply it.
- Arnaldo
> ~# strace perf
> execve("/usr/sbin/perf", ["perf"], [/* 12 vars */]) = -1 ENOMEM (Cannot allocate memory)
> --- SIGSEGV {si_signo=SIGSEGV, si_code=SI_KERNEL, si_addr=0} ---
> +++ killed by SIGSEGV +++
> Segmentation fault
>
> objdump -x shows that .bss section has a huge size of 24Mbytes:
>
> 27 .bss 016baca8 101cebb8 101cebb8 001cd988 2**3
>
> With especially the following objects having quite big size
>
> 10205f80 l O .bss 00140000 runtime_cycles_stats
> 10345f80 l O .bss 00140000 runtime_stalled_cycles_front_stats
> 10485f80 l O .bss 00140000 runtime_stalled_cycles_back_stats
> 105c5f80 l O .bss 00140000 runtime_branches_stats
> 10705f80 l O .bss 00140000 runtime_cacherefs_stats
> 10845f80 l O .bss 00140000 runtime_l1_dcache_stats
> 10985f80 l O .bss 00140000 runtime_l1_icache_stats
> 10ac5f80 l O .bss 00140000 runtime_ll_cache_stats
> 10c05f80 l O .bss 00140000 runtime_itlb_cache_stats
> 10d45f80 l O .bss 00140000 runtime_dtlb_cache_stats
> 10e85f80 l O .bss 00140000 runtime_cycles_in_tx_stats
> 10fc5f80 l O .bss 00140000 runtime_transaction_stats
> 11105f80 l O .bss 00140000 runtime_elision_stats
> 11245f80 l O .bss 00140000 runtime_topdown_total_slots
> 11385f80 l O .bss 00140000 runtime_topdown_slots_retired
> 114c5f80 l O .bss 00140000 runtime_topdown_slots_issued
> 11605f80 l O .bss 00140000 runtime_topdown_fetch_bubbles
> 11745f80 l O .bss 00140000 runtime_topdown_recovery_bubbles
>
> This is due to commit 4d255766d28b1 ("perf: Bump max number of cpus
> to 1024"), because many tables are sized with MAX_NR_CPUS
>
> This patch gives the opportunity to redefine MAX_NR_CPUS via
>
> make EXTRA_CFLAGS=-DMAX_NR_CPUS=1
>
> Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
> ---
> tools/perf/perf.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/tools/perf/perf.h b/tools/perf/perf.h
> index dc442ba21bf6..a9db563da0a9 100644
> --- a/tools/perf/perf.h
> +++ b/tools/perf/perf.h
> @@ -23,7 +23,9 @@ static inline unsigned long long rdclock(void)
> return ts.tv_sec * 1000000000ULL + ts.tv_nsec;
> }
>
> +#ifndef MAX_NR_CPUS
> #define MAX_NR_CPUS 1024
> +#endif
>
> extern const char *input_name;
> extern bool perf_host, perf_guest;
> --
> 2.13.3
next prev parent reply other threads:[~2018-05-03 13:40 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-22 11:20 [PATCH] perf tools: allow overriding MAX_NR_CPUS at compile time Christophe Leroy
2017-09-22 14:09 ` Arnaldo Carvalho de Melo
2018-05-03 13:40 ` Arnaldo Carvalho de Melo [this message]
2018-08-01 9:37 ` Christophe LEROY
2018-08-01 14:40 ` Arnaldo Carvalho de Melo
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