lkml.org 
[lkml]   [2010]   [May]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH] perf/trace: use read() instead of lseek() in trace_event_read.c:skip()
From
Date
Hi,

Here's a small fix for a problem affecting live-mode, introduced in the
past day or so:

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>
---
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;
--
1.6.4.GIT




\
 
 \ /
  Last update: 2010-05-05 06:05    [W:0.052 / U:0.500 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site