From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752426AbeDLNdL (ORCPT ); Thu, 12 Apr 2018 09:33:11 -0400 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:55574 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751711AbeDLNdK (ORCPT ); Thu, 12 Apr 2018 09:33:10 -0400 From: Thomas Richter To: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, acme@kernel.org Cc: brueckner@linux.vnet.ibm.com, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, Thomas Richter Subject: [PATCH] perf record: Change warning for missing sysfs entry to debug Date: Thu, 12 Apr 2018 15:32:46 +0200 X-Mailer: git-send-email 2.13.5 X-TM-AS-GCONF: 00 x-cbid: 18041213-0040-0000-0000-0000044CC47E X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 18041213-0041-0000-0000-000020F0F88F Message-Id: <20180412133246.92801-1-tmricht@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:,, definitions=2018-04-12_07:,, signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1709140000 definitions=main-1804120135 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Using perf on 4.16.0 kernel on s390 shows warning failed: can't open node sysfs data each time I run command perf record ... for example: [root@s35lp76 perf]# ./perf record -e rB0000 -- sleep 1 [ perf record: Woken up 1 times to write data ] failed: can't open node sysfs data [ perf record: Captured and wrote 0.001 MB perf.data (4 samples) ] [root@s35lp76 perf]# It turns out commit e2091cedd51bf ("perf tools: Add MEM_TOPOLOGY feature to perf data file") tries to open directory named /sys/devices/system/node/ which does not exist on s390. This is the call stack: __cmd_record +---> perf_session__write_header +---> perf_header__adds_write +---> do_write_feat +---> write_mem_topology +---> build_mem_topology prints warning The issue starts in do_write_feat() which unconditionally loops over all features and now includes HEADER_MEM_TOPOLOGY and calls write_mem_topology(). Function record__init_features() at the beginning of __cmd_record() sets all features and then turns off some of them. Fix this by changing the warning to a level 2 debug output statement. So it is only shown when debug level 2 or higher is set. Signed-off-by: Thomas Richter --- tools/perf/util/header.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 121df1683c36..a8bff2178fbc 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -1320,7 +1320,8 @@ static int build_mem_topology(struct memory_node *nodes, u64 size, u64 *cntp) dir = opendir(path); if (!dir) { - pr_warning("failed: can't open node sysfs data\n"); + pr_debug2("%s: could't read %s, does this arch have topology information?\n", + __func__, path); return -1; } -- 2.14.3