From: tip-bot for Thomas Richter <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, hpa@zytor.com,
brueckner@linux.vnet.ibm.com, heiko.carstens@de.ibm.com,
tmricht@linux.ibm.com, tglx@linutronix.de, acme@redhat.com,
mingo@kernel.org, schwidefsky@de.ibm.com
Subject: [tip:perf/urgent] perf record: Change warning for missing sysfs entry to debug
Date: Sun, 15 Apr 2018 23:47:35 -0700 [thread overview]
Message-ID: <tip-4f75f1cbf95e2f0853cd229d042b203931b899af@git.kernel.org> (raw)
In-Reply-To: <20180412133246.92801-1-tmricht@linux.ibm.com>
Commit-ID: 4f75f1cbf95e2f0853cd229d042b203931b899af
Gitweb: https://git.kernel.org/tip/4f75f1cbf95e2f0853cd229d042b203931b899af
Author: Thomas Richter <tmricht@linux.ibm.com>
AuthorDate: Thu, 12 Apr 2018 15:32:46 +0200
Committer: Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Fri, 13 Apr 2018 09:59:56 -0300
perf record: Change warning for missing sysfs entry to debug
Using perf on 4.16.0 kernel on s390 shows this 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 <tmricht@linux.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Hendrik Brueckner <brueckner@linux.vnet.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Link: http://lkml.kernel.org/r/20180412133246.92801-1-tmricht@linux.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
| 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--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;
}
prev parent reply other threads:[~2018-04-16 6:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-12 13:32 [PATCH] perf record: Change warning for missing sysfs entry to debug Thomas Richter
2018-04-12 17:22 ` Arnaldo Carvalho de Melo
2018-04-16 6:47 ` tip-bot for Thomas Richter [this message]
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