Re: [BUG] perf report: garbage output with event grouping

From: Jiri Olsa
Date: Wed Jun 26 2013 - 05:15:41 EST


On Wed, Jun 26, 2013 at 10:42:49AM +0200, Stephane Eranian wrote:
> Hi,
>
>
> $ perf record -e 'cpi{cycles,instructions}' noploop 5
>
> $ perf report --stdio --group
> # group: ^P^Q<A0>\{cycles,instructions}
> # ========
> #
> # Samples: 39K of event '^P^Q<A0>\ { cycles, instructions }'
> # Event count (approx.): 37782563692
> #
> # Overhead Command Shared Object Symbol
> # ................ ....... ................. ...........................
> #
> 99.91% 99.98% noploop noploop [.] main
> 0.06% -nan% noploop [kernel.kallsyms] [k] read_hpet
> 0.01% 0.01% noploop [kernel.kallsyms] [k] __acct_update_integrals
> 0.01% -nan% noploop [kernel.kallsyms] [k] raise_softirq
> 0.01% -nan% noploop [kernel.kallsyms] [k] apic_timer_interrupt
> 0.01% -nan% noploop [kernel.kallsyms] [k] __do_softirq
> 0.01% -nan% noploop [kernel.kallsyms] [k] common_interrupt
> 0.00% 0.00% noploop [kernel.kallsyms] [k] intel_pmu_enable_all
> 0.00% 0.01% noploop [kernel.kallsyms] [k] cpuacct_account_field
> 0.00% 0.01% noploop [kernel.kallsyms] [k] __local_bh_enable
>
>
> 1. The group name is garbage if not anonymous group.
> 2. arithmetic error in the overhead columns leading to NaN.
> 3. I assume the Overhead column order is the group event order. Is that right?

hi

1) attached patch fixies that for me
2) I cannot reproduce this one on acme's tree
3) right, and we do need event names there ;-)

---
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index 738d3b8..673d98c 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -2089,7 +2089,7 @@ static int process_group_desc(struct perf_file_section *section __maybe_unused,
evsel->leader = evsel;
/* {anon_group} is a dummy name */
if (strcmp(desc[i].name, "{anon_group}"))
- evsel->group_name = desc[i].name;
+ evsel->group_name = strdup(desc[i].name);
evsel->nr_members = desc[i].nr_members;

if (i >= nr_groups || nr > 0) {
--
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