Commit cbb5cf7f authored May 04, 2010 by Tom Zanussi Committed by Frederic Weisbecker May 20, 2010

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 d00a47cc 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>

parent 537b60d1

tools/perf/util/trace-event-read.c

+13 −6

Original line number	Original line	Diff line number	Diff line
	@@ -53,12 +53,6 @@ static unsigned long page_size;
	static ssize_t calc_data_size;		static ssize_t calc_data_size;
	static bool repipe;		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)		static int do_read(int fd, void *buf, int size)
	{		{
	int rsize = size;		int rsize = size;
	@@ -98,6 +92,19 @@ static int read_or_die(void *data, int size)
	return r;		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)		static unsigned int read4(void)
	{		{
	unsigned int data;		unsigned int data;