Messages in this thread Patch in this message | | | Date | Fri, 17 May 2013 10:16:40 +0800 | Subject | [Bug] ARM 'perf' regression by commit a43cb95d5 | From | Ming Lei <> |
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Hi,
The commit a43cb95d5(dump_stack: unify debug information printed by show_regs()) caused ARM perf regression, then 'perf top' outputs mistakenly, see [1]. The correct output should be [2], which can be got after reverting the commit or doing it partly by the one line change below:
diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index f219703..89bc3a4 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -225,7 +225,7 @@ void __show_regs(struct pt_regs *regs) unsigned long flags; char buf[64];
- show_regs_print_info(KERN_DEFAULT); + //show_regs_print_info(KERN_DEFAULT);
Looks a bit weird, anyone can give a hint?
Thanks, -- Ming Lei
[1], 'perf top' mistaken output Samples: 17K of event 'cpu-clock', Event count (approx.): 3516532661 97.51% [smsc95xx] [k] 0x013645b8 0.21% libc-2.15.so [.] strstr 0.14% libc-2.15.so [.] strchr 0.12% libc-2.15.so [.] strcmp 0.12% perf [.] perf_evsel__parse_sample 0.09% perf [.] symbols__insert 0.09% perf [.] dso__load_sym 0.08% perf [.] perf_top__mmap_read_idx 0.08% perf [.] symbol_filter 0.07% libc-2.15.so [.] memchr 0.07% libc-2.15.so [.] memset 0.07% perf [.] internal_cplus_demangle 0.06% perf [.] sort__dso_cmp 0.06% libc-2.15.so [.] strncmp 0.06% perf [.] add_hist_entry.isra.2 0.06% perf [.] dso__find_symbol 0.06% libc-2.15.so [.] _int_malloc 0.05% perf [.] 0x00010d60 0.04% libc-2.15.so [.] memcpy 0.04% perf [.] map__find_symbol 0.04% perf [.] rb_next 0.04% libelf-0.154.so [.] gelf_getsym
[2], 'perf top' correct output Samples: 46K of event 'cpu-clock', Event count (approx.): 937128704 96.44% [kernel] [k] cpuidle_enter_state 0.19% libc-2.15.so [.] strstr 0.16% [kernel] [k] kallsyms_expand_symbol.clone.0 0.13% [kernel] [k] _raw_spin_unlock_irq 0.13% [kernel] [k] _raw_spin_unlock_irqrestore 0.10% [kernel] [k] format_decode 0.10% perf [.] perf_top__mmap_read_idx 0.10% perf [.] rb_next 0.09% perf [.] dso__find_symbol 0.08% [kernel] [k] vsnprintf 0.08% perf [.] add_hist_entry.isra.2 0.08% libc-2.15.so [.] strcmp 0.08% libc-2.15.so [.] memchr 0.07% perf [.] sort__dso_cmp 0.07% libc-2.15.so [.] strchr 0.07% [kernel] [k] number.clone.1 0.07% perf [.] map__process_kallsym_symbol 0.06% [kernel] [k] memcpy 0.05% perf [.] perf_evsel__parse_sample 0.05% libc-2.15.so [.] _int_malloc 0.05% libc-2.15.so [.] memcpy 0.05% perf [.] perf_event__preprocess_sample
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