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

From: Akihiro Nagai
Date: Thu Jul 21 2011 - 05:36:59 EST


(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@xxxxxxxxxxx>
Cc: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
Cc: Frederic Weisbecker<fweisbec@xxxxxxxxx>
Cc: Paul Mackerras<paulus@xxxxxxxxx>
Cc: Ingo Molnar<mingo@xxxxxxx>
Cc: Arnaldo Carvalho de Melo<acme@xxxxxxxxxxxxx>
Cc: David Ahern<dsahern@xxxxxxxxx>
Cc: Masami Hiramatsu<masami.hiramatsu.pt@xxxxxxxxxxx>
---

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>");

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