Re: [PATCH -tip v2 3/6] perf script: resolve DSOs and symbols for user-space

Akihiro Nagai
2011-07-21T09:36:56Z

(2011/07/18 1:20), David Ahern wrote:
> On 07/17/2011 03:30 AM, Akihiro Nagai wrote:
>> Resolve user-space DSOs and symbols.
>> Latest perf-script can resolve DSOs and symbols for only kernel
>> and kernel modules. This patch resolves them for other
>> executable binaries.
>
> The description is a bit misleading. perf script does resolve symbols
> for userspace. e.g., the example in the bug fix I submitted in May:
> https://lkml.org/lkml/2011/5/30/223
>
> Do you look into why the cpumode setting is not working that you have to
> try specific settings?
Indeed, perf already can resolve user-space symbols and DSOs if cpumode has
the flag PERF_RECORD_MISC_USER. I found this change is incorrect.
To solve this, I'd like to set both flags PERF_RECORD_MISC_KERNEL and USER
to BTS records, because BTS traces both kernel and user space while it
generates interrupts.

And also, I think there is the probrem in thread__find_addr_map().
When this function is called with cpumode that is set (PERF_RECORD_MISC_KERNEL | USER),
this function processes only PERF_RECORD_MISC_KERNEL. So, I'd like to fix it too.

Thank you.
>
> David
>
>
>>
>> # perf script -f ip,addr,sym,dso
>> 3f03e016b0 ffffffff814675d2 irq_return ([kernel.kallsyms])
>> 3f03e016b0 ffffffff814675d2 irq_return ([kernel.kallsyms])
>> 3f03e04b80 3f03e016b3 _start (/lib64/ld-2.14.so)
>> 3f03e04b80 ffffffff814675d2 irq_return ([kernel.kallsyms])
>> 3f03e04ba6 ffffffff814675d2 irq_return ([kernel.kallsyms])
>> 3f03e04bad ffffffff814675d2 irq_return ([kernel.kallsyms])
>> 3f03e04c1d 3f03e04bfb _dl_start (/lib64/ld-2.14.so)
>> 3f03e04c00 3f03e04c21 _dl_start (/lib64/ld-2.14.so)
>> 3f03e04c00 3f03e04c21 _dl_start (/lib64/ld-2.14.so)
>> [snip]
>>
>> Signed-off-by: Akihiro Nagai<akihiro.nagai.hw@hitachi.com>
>> Cc: Peter Zijlstra<peterz@infradead.org>
>> Cc: Frederic Weisbecker<fweisbec@gmail.com>
>> Cc: Paul Mackerras<paulus@samba.org>
>> Cc: Ingo Molnar<mingo@elte.hu>
>> Cc: Arnaldo Carvalho de Melo<acme@infradead.org>
>> Cc: David Ahern<dsahern@gmail.com>
>> Cc: Masami Hiramatsu<masami.hiramatsu.pt@hitachi.com>
>> ---
>>
>> tools/perf/builtin-script.c | 4 ++++
>> tools/perf/util/event.c | 5 +++++
>> 2 files changed, 9 insertions(+), 0 deletions(-)
>>
>> diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
>> index b3e0951..2356198 100644
>> --- a/tools/perf/builtin-script.c
>> +++ b/tools/perf/builtin-script.c
>> @@ -328,6 +328,10 @@ static void print_sample_addr(union perf_event *event,
>>
>> thread__find_addr_map(thread, session, cpumode, MAP__FUNCTION,
>> event->ip.pid, sample->addr,&al);
>> + /* try to resolve for user space */
>> + if (!al.map)
>> + thread__find_addr_map(thread, session, PERF_RECORD_MISC_USER,
>> + MAP__FUNCTION, event->ip.pid, sample->addr,&al);
>> if (!al.map)
>> thread__find_addr_map(thread, session, cpumode, MAP__VARIABLE,
>> event->ip.pid, sample->addr,&al);
>> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
>> index 3c1b8a6..49a9315 100644
>> --- a/tools/perf/util/event.c
>> +++ b/tools/perf/util/event.c
>> @@ -771,6 +771,11 @@ int perf_event__preprocess_sample(const union perf_event *event,
>>
>> thread__find_addr_map(thread, session, cpumode, MAP__FUNCTION,
>> event->ip.pid, event->ip.ip, al);
>> + /* try to resolve for user space */
>> + if (!al->map)
>> + thread__find_addr_map(thread, session, PERF_RECORD_MISC_USER,
>> + MAP__FUNCTION, event->ip.pid, event->ip.ip, al);
>> +
>> dump_printf(" ...... dso: %s\n",
>> al->map ? al->map->dso->long_name :
>> al->level == 'H' ? "[hypervisor]" : "<not found>");
>>