[tip:perf/core] perf: Use read() instead of lseek() in trace_event_read.c:skip()
in [Kernel]
|
Prev: parisc: set ARCH_KMALLOC_MINALIGN
Next: perf: Use read() instead of lseek() in trace_event_read.c:skip()
From: tip-bot for Tom Zanussi on 20 May 2010 09:00 Commit-ID: cbb5cf7ff6b298beacfe23db3386335b0b9c0a2d Gitweb: http://git.kernel.org/tip/cbb5cf7ff6b298beacfe23db3386335b0b9c0a2d Author: Tom Zanussi <tzanussi(a)gmail.com> AuthorDate: Tue, 4 May 2010 23:02:10 -0500 Committer: Frederic Weisbecker <fweisbec(a)gmail.com> CommitDate: Thu, 20 May 2010 08:37:17 +0200 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(a)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(a)gmail.com> Cc: Ingo Molnar <mingo(a)elte.hu> Cc: Peter Zijlstra <a.p.zijlstra(a)chello.nl> Cc: Arnaldo Carvalho de Melo <acme(a)redhat.com> Cc: Paul Mackerras <paulus(a)samba.org> LKML-Reference: <1273032130.6383.28.camel(a)tropicana> Signed-off-by: Frederic Weisbecker <fweisbec(a)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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |