From: Frederic Weisbecker <fweisbec@gmail.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: LKML <linux-kernel@vger.kernel.org>,
Tom Zanussi <tzanussi@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Paul Mackerras <paulus@samba.org>,
Frederic Weisbecker <fweisbec@gmail.com>
Subject: [PATCH 1/3] perf: Use read() instead of lseek() in trace_event_read.c:skip()
Date: Thu, 20 May 2010 11:44:17 +0200 [thread overview]
Message-ID: <1274348659-15417-2-git-send-regression-fweisbec@gmail.com> (raw)
In-Reply-To: <1274348659-15417-1-git-send-regression-fweisbec@gmail.com>
From: Tom Zanussi <tzanussi@gmail.com>
This is a small fix for a problem affecting live-mode, introduced
recently:
root@tropicana:~# perf trace rwtop
perf trace started with Perl
script /root/libexec/perf-core/scripts/perl/rwtop.pl
Fatal: did not read header event
commit d00a47cce569a3e660a8c9de5d57af28d6a9f0f7 added a skip()
function to skip over e.g. header_page, but this doesn't work for
live mode. This patch re-implements skip() to use read() instead of
lseek() to fix that.
Signed-off-by: Tom Zanussi <tzanussi@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1273032130.6383.28.camel@tropicana>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
---
tools/perf/util/trace-event-read.c | 19 +++++++++++++------
1 files changed, 13 insertions(+), 6 deletions(-)
diff --git a/tools/perf/util/trace-event-read.c b/tools/perf/util/trace-event-read.c
index cb54cd0..f55cc3a 100644
--- a/tools/perf/util/trace-event-read.c
+++ b/tools/perf/util/trace-event-read.c
@@ -53,12 +53,6 @@ static unsigned long page_size;
static ssize_t calc_data_size;
static bool repipe;
-/* If it fails, the next read will report it */
-static void skip(int size)
-{
- lseek(input_fd, size, SEEK_CUR);
-}
-
static int do_read(int fd, void *buf, int size)
{
int rsize = size;
@@ -98,6 +92,19 @@ static int read_or_die(void *data, int size)
return r;
}
+/* If it fails, the next read will report it */
+static void skip(int size)
+{
+ char buf[BUFSIZ];
+ int r;
+
+ while (size) {
+ r = size > BUFSIZ ? BUFSIZ : size;
+ read_or_die(buf, r);
+ size -= r;
+ };
+}
+
static unsigned int read4(void)
{
unsigned int data;
--
1.6.2.3
next prev parent reply other threads:[~2010-05-20 9:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-05-20 9:44 [GIT PULL] perf fixes Frederic Weisbecker
2010-05-20 9:44 ` Frederic Weisbecker [this message]
2010-05-20 9:44 ` [PATCH 2/3] perf: Comply with new rcu checks API Frederic Weisbecker
2010-05-20 9:44 ` [PATCH 3/3] perf: Fix unaligned accesses while fetching trace values Frederic Weisbecker
2010-05-20 12:40 ` [GIT PULL] perf fixes Ingo Molnar
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