Messages in this thread | | | Subject | Re: [PATCH] perf tools: allow overriding MAX_NR_CPUS at compile time | From | Christophe LEROY <> | Date | Wed, 1 Aug 2018 11:37:30 +0200 |
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Le 03/05/2018 à 15:40, Arnaldo Carvalho de Melo a écrit : > 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.
Did you finally apply it ? I can't see it in linux-next. Will it be merged into 4.19 ?
Thanks Christophe
> > 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
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