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authorTom Zanussi <tzanussi@gmail.com>2010-05-04 23:02:10 -0500
committerFrederic Weisbecker <fweisbec@gmail.com>2010-05-20 08:37:17 +0200
commitcbb5cf7ff6b298beacfe23db3386335b0b9c0a2d (patch)
tree153901937a7ce3acffc536c48652e0d87a52685b
parent537b60d17894b7c19a6060feae40299d7109d6e7 (diff)
downloadlinux-2.6.34-ux500-cbb5cf7ff6b298beacfe23db3386335b0b9c0a2d.tar.gz
perf: Use read() instead of lseek() in trace_event_read.c:skip()
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>
-rw-r--r--tools/perf/util/trace-event-read.c19
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 cb54cd002f4..f55cc3a765a 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;