This is a note to let you know that I've just added the patch titled
perf cputopo: Fix CPU topology reading on s/390
to the 5.16-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
perf-cputopo-fix-cpu-topology-reading-on-s-390.patch
and it can be found in the queue-5.16 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a6e62743621ea29bea461774c0bcc68e5de59068 Mon Sep 17 00:00:00 2001
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Date: Wed, 24 Nov 2021 10:03:43 +0100
Subject: perf cputopo: Fix CPU topology reading on s/390
From: Thomas Richter <tmricht@xxxxxxxxxxxxx>
commit a6e62743621ea29bea461774c0bcc68e5de59068 upstream.
Commit fdf1e29b6118c18f ("perf expr: Add metric literals for topology.")
fails on s390:
# ./perf test -Fv 7
...
# FAILED tests/expr.c:173 #num_dies >= #num_packages
---- end ----
Simple expression parser: FAILED!
#
Investigating this issue leads to these functions:
build_cpu_topology()
+--> has_die_topology(void)
{
struct utsname uts;
if (uname(&uts) < 0)
return false;
if (strncmp(uts.machine, "x86_64", 6))
return false;
....
}
which always returns false on s390. The caller build_cpu_topology()
checks has_die_topology() return value. On false the
the struct cpu_topology::die_cpu_list is not contructed and has zero
entries. This leads to the failing comparison: #num_dies >= #num_packages.
s390 of course has a positive number of packages.
Fix this by adding s390 architecture to support CPU die list.
Output after:
# ./perf test -Fv 7
7: Simple expression parser :
--- start ---
division by zero
syntax error
---- end ----
Simple expression parser: Ok
#
Fixes: fdf1e29b6118c18f ("perf expr: Add metric literals for topology.")
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Ian Rogers <irogers@xxxxxxxxxx>
Cc: Sumanth Korikkar <sumanthk@xxxxxxxxxxxxx>
Cc: Sven Schnelle <svens@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20211124090343.9436-1-tmricht@xxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
tools/perf/util/cputopo.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/tools/perf/util/cputopo.c
+++ b/tools/perf/util/cputopo.c
@@ -165,7 +165,8 @@ static bool has_die_topology(void)
if (uname(&uts) < 0)
return false;
- if (strncmp(uts.machine, "x86_64", 6))
+ if (strncmp(uts.machine, "x86_64", 6) &&
+ strncmp(uts.machine, "s390x", 5))
return false;
scnprintf(filename, MAXPATHLEN, DIE_CPUS_FMT,
Patches currently in stable-queue which might be from tmricht@xxxxxxxxxxxxx are
queue-5.16/perf-cputopo-fix-cpu-topology-reading-on-s-390.patch
