linux-kernel - Re: [BUG] perf: buildid not managed properly when cmd path is relative

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Date:	Tue, 1 Jun 2010 15:38:37 -0300
From:	Arnaldo Carvalho de Melo <acme@...radead.org>
To:	Stephane Eranian <eranian@...gle.com>
Cc:	linux-kernel@...r.kernel.org, Ingo Molnar <mingo@...e.hu>,
	perfmon2-devel@...ts.sf.net, eranian@...il.com,
	"David S. Miller" <davem@...emloft.net>,
	Frédéric Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Stephane Eranian <eranian@...gle.com>,
	Tom Zanussi <tzanussi@...il.com>
Subject: Re: [BUG] perf: buildid not managed properly when cmd path is
 relative

Em Thu, May 27, 2010 at 03:46:16PM +0200, Stephane Eranian escreveu:
> I ran into another problem while running more tests with perf record,
> perf buildid-list.
 
> I do the following:
 
> $ perf record foo/noploop 5 ; perf buildid-list
> 54b1e7cc3cf52e0db255aab44ce7538eb62655b8 [kernel.kallsyms]
> 875ae61623e89f408b425ca0486a9ec99e3ac73e
> /home/eranian/perfmon/official/tip/build/tools/perf/foo/noploop
> 
> I know I have samples in noploop:
> $ perf report -D
> 0x10a0 [0x20]: PERF_RECORD_SAMPLE(IP, 2): 14721/14721: 0x4006d6 period: 2351576
>  ... thread: noploop:14721
>  ...... dso: ./foo/noploop

> But if I ask with buildid-list (like per-archive is doing) then I get:
> $ perf buildid-list --with-hits
> 54b1e7cc3cf52e0db255aab44ce7538eb62655b8 [kernel.kallsyms]
> 0000000000000000000000000000000000000000 ./foo/noploop

> The builid is bogus for noploop and it is relative path not full anymore.

Hi Stephane,

	Can you please try the following patch?

Thanks in advance,

- Arnaldo

>From 9d146ff3c994634c529396442a4a96b0e58809e2 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@...hat.com>
Date: Tue, 1 Jun 2010 12:37:05 -0300
Subject: [PATCH 1/1] perf buildid-list: Fix --with-hits event processing
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When we use plain 'perf buildid-list' we use only what is in the buildid
table in the perf.data header. And those have absolute pathnames because
at 'perf record' time we used __perf_session__process_events and that
doesn't sets up the path shortening code in map__new() that happens if
symbol_conf.full_paths is false, the default.

On the other hand, when we use 'perf buildid-list --with-hits' we
process all the events using perf_session__process_events, adding
entries to the global DSO list _after_ removing the current directory
from the DSO name, for presentation purposes.

Because of that we end up having two entries in the DSO list when
recording events for binaries using relative pathnames.

Fix it minimally by setting symbol_conf.full_paths to true when marking
the DSOs with hits in 'perf buildid-list --with-hits', as used by 'perf
archive'

Right fix longer term is to shorten the path only at presentation time.
Will be done for 2.6.36.

Reported-by: Stephane Eranian <eranian@...gle.com>
Cc: David S. Miller <davem@...emloft.net>
Cc: Frédéric Weisbecker <fweisbec@...il.com>
Cc: Ingo Molnar <mingo@...e.hu>
Cc: Mike Galbraith <efault@....de>
Cc: Paul Mackerras <paulus@...ba.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Stephane Eranian <eranian@...gle.com>
Cc: Tom Zanussi <tzanussi@...il.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/builtin-buildid-list.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/tools/perf/builtin-buildid-list.c b/tools/perf/builtin-buildid-list.c
index 44a47e1..9989072 100644
--- a/tools/perf/builtin-buildid-list.c
+++ b/tools/perf/builtin-buildid-list.c
@@ -43,8 +43,10 @@ static int __cmd_buildid_list(void)
 	if (session == NULL)
 		return -1;
 
-	if (with_hits)
+	if (with_hits) {
+		symbol_conf.full_paths = true;
 		perf_session__process_events(session, &build_id__mark_dso_hit_ops);
+	}
 
 	perf_session__fprintf_dsos_buildid(session, stdout, with_hits);
 
-- 
1.6.5.2

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