Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752959AbcDRKsv (ORCPT ); Mon, 18 Apr 2016 06:48:51 -0400 Received: from mail.kernel.org ([198.145.29.136]:34300 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752933AbcDRKsr (ORCPT ); Mon, 18 Apr 2016 06:48:47 -0400 From: lizf@kernel.org To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Borislav Petkov , David Ahern , Frederic Weisbecker , Jiri Olsa , Kan Liang , Stephane Eranian , Wang Nan , Zefan Li Subject: [PATCH 3.4 32/92] perf header: Fixup reading of HEADER_NRCPUS feature Date: Mon, 18 Apr 2016 18:45:37 +0800 Message-Id: <1460976397-5688-32-git-send-email-lizf@kernel.org> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1460976338-5631-1-git-send-email-lizf@kernel.org> References: <1460976338-5631-1-git-send-email-lizf@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3263 Lines: 104 From: Arnaldo Carvalho de Melo 3.4.112-rc1 review patch. If anyone has any objections, please let me know. ------------------ commit caa470475d9b59eeff093ae650800d34612c4379 upstream. The original patch introducing this header wrote the number of CPUs available and online in one order and then swapped those values when reading, fix it. Before: # perf record usleep 1 # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 4 # nrcpus avail : 4 # echo 0 > /sys/devices/system/cpu/cpu2/online # perf record usleep 1 # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 4 # nrcpus avail : 3 # echo 0 > /sys/devices/system/cpu/cpu1/online # perf record usleep 1 # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 4 # nrcpus avail : 2 After the fix, bringing back the CPUs online: # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 2 # nrcpus avail : 4 # echo 1 > /sys/devices/system/cpu/cpu2/online # perf record usleep 1 # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 3 # nrcpus avail : 4 # echo 1 > /sys/devices/system/cpu/cpu1/online # perf record usleep 1 # perf report --header-only | grep 'nrcpus \(online\|avail\)' # nrcpus online : 4 # nrcpus avail : 4 Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Kan Liang Cc: Stephane Eranian Cc: Wang Nan Fixes: fbe96f29ce4b ("perf tools: Make perf.data more self-descriptive (v8)") Link: http://lkml.kernel.org/r/20150911153323.GP23511@kernel.org Signed-off-by: Arnaldo Carvalho de Melo [lizf: Backported to 3.4: fix it by saving values in an array and then print it in reverse order] Signed-off-by: Zefan Li --- tools/perf/util/header.c | 22 ++++++++-------------- 1 file changed, 8 insertions(+), 14 deletions(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index c0b70c6..5a4482c 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1060,25 +1060,19 @@ static void print_cpudesc(struct perf_header *ph, int fd, FILE *fp) static void print_nrcpus(struct perf_header *ph, int fd, FILE *fp) { ssize_t ret; - u32 nr; + u32 nr[2]; ret = read(fd, &nr, sizeof(nr)); if (ret != (ssize_t)sizeof(nr)) - nr = -1; /* interpreted as error */ + nr[0] = nr[1] = -1; /* interpreted as error */ - if (ph->needs_swap) - nr = bswap_32(nr); - - fprintf(fp, "# nrcpus online : %u\n", nr); - - ret = read(fd, &nr, sizeof(nr)); - if (ret != (ssize_t)sizeof(nr)) - nr = -1; /* interpreted as error */ - - if (ph->needs_swap) - nr = bswap_32(nr); + if (ph->needs_swap) { + nr[0] = bswap_32(nr[0]); + nr[1] = bswap_32(nr[1]); + } - fprintf(fp, "# nrcpus avail : %u\n", nr); + fprintf(fp, "# nrcpus online : %u\n", nr[1]); + fprintf(fp, "# nrcpus avail : %u\n", nr[0]); } static void print_version(struct perf_header *ph, int fd, FILE *fp) -- 1.9.1