File perf-bench-Fix-numa-testcase-to-check-if-CPU-used-to-bind-task-is-online.patch of Package perf.24474
From: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Date: Tue, 12 Apr 2022 22:10:58 +0530
Subject: perf bench: Fix numa testcase to check if CPU used to bind task is
online
Git-commit: 8cb7a188ac33b71ec24a9081d1521f46dcab53c4
Patch-mainline: v5.18-rc3
References: bsc#1198595
Perf numa bench test fails with error:
Testcase:
./perf bench numa mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp 1 --no-data_rand_walk
Failure snippet:
<<>>
Running 'numa/mem' benchmark:
# Running main, "perf bench numa numa-mem -p 2 -t 1 -P 1024 -C 0,8 -M 1,0 -s 20 -zZq --thp 1 --no-data_rand_walk"
perf: bench/numa.c:333: bind_to_cpumask: Assertion `!(ret)' failed.
<<>>
The Testcases uses CPU's 0 and 8. In function "parse_setup_cpu_list",
There is check to see if cpu number is greater than max cpu's possible
in the system ie via "if (bind_cpu_0 >= g->p.nr_cpus || bind_cpu_1 >=
g->p.nr_cpus) {".
But it could happen that system has say 48 CPU's, but only number of
online CPU's is 0-7. Other CPU's are offlined. Since "g->p.nr_cpus" is
48, so function will go ahead and set bit for CPU 8 also in cpumask (
td->bind_cpumask).
bind_to_cpumask function is called to set affinity using
sched_setaffinity and the cpumask. Since the CPU8 is not present, set
affinity will fail here with EINVAL.
Fix this issue by adding a check to make sure that, CPU's provided in
the input argument values are online before proceeding further and skip
the test. For this, include new helper function "is_cpu_online" in
"tools/perf/util/header.c".
Since "BIT(x)" definition will get included from header.h, remove
that from bench/numa.c
Reported-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Signed-off-by: Athira Jajeev <atrajeev@linux.vnet.ibm.com>
Tested-by: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.vnet.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nageswara R Sastry <rnsastry@linux.ibm.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20220412164059.42654-2-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Tony Jones <tonyj@suse.de>
---
tools/perf/bench/numa.c | 8 ++++++--
tools/perf/util/header.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++++
tools/perf/util/header.h | 1 +
3 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index f2640179ada9..c838c248aa2c 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -34,6 +34,7 @@
#include <linux/numa.h>
#include <linux/zalloc.h>
+#include "../util/header.h"
#include <numa.h>
#include <numaif.h>
@@ -585,6 +586,11 @@ static int parse_setup_cpu_list(void)
return -1;
}
+ if (is_cpu_online(bind_cpu_0) != 1 || is_cpu_online(bind_cpu_1) != 1) {
+ printf("\nTest not applicable, bind_cpu_0 or bind_cpu_1 is offline\n");
+ return -1;
+ }
+
BUG_ON(bind_cpu_0 < 0 || bind_cpu_1 < 0);
BUG_ON(bind_cpu_0 > bind_cpu_1);
@@ -752,8 +758,6 @@ static int parse_nodes_opt(const struct option *opt __maybe_unused,
return parse_node_list(arg);
}
-#define BIT(x) (1ul << x)
-
static inline uint32_t lfsr_32(uint32_t lfsr)
{
const uint32_t taps = BIT(1) | BIT(5) | BIT(6) | BIT(31);
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index d546ff724dbe..a27132e5a5ef 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -983,6 +983,57 @@ static int write_dir_format(struct feat_fd *ff,
return do_write(ff, &data->dir.version, sizeof(data->dir.version));
}
+/*
+ * Check whether a CPU is online
+ *
+ * Returns:
+ * 1 -> if CPU is online
+ * 0 -> if CPU is offline
+ * -1 -> error case
+ */
+int is_cpu_online(unsigned int cpu)
+{
+ char *str;
+ size_t strlen;
+ char buf[256];
+ int status = -1;
+ struct stat statbuf;
+
+ snprintf(buf, sizeof(buf),
+ "/sys/devices/system/cpu/cpu%d", cpu);
+ if (stat(buf, &statbuf) != 0)
+ return 0;
+
+ /*
+ * Check if /sys/devices/system/cpu/cpux/online file
+ * exists. Some cases cpu0 won't have online file since
+ * it is not expected to be turned off generally.
+ * In kernels without CONFIG_HOTPLUG_CPU, this
+ * file won't exist
+ */
+ snprintf(buf, sizeof(buf),
+ "/sys/devices/system/cpu/cpu%d/online", cpu);
+ if (stat(buf, &statbuf) != 0)
+ return 1;
+
+ /*
+ * Read online file using sysfs__read_str.
+ * If read or open fails, return -1.
+ * If read succeeds, return value from file
+ * which gets stored in "str"
+ */
+ snprintf(buf, sizeof(buf),
+ "devices/system/cpu/cpu%d/online", cpu);
+
+ if (sysfs__read_str(buf, &str, &strlen) < 0)
+ return status;
+
+ status = atoi(str);
+
+ free(str);
+ return status;
+}
+
#ifdef HAVE_LIBBPF_SUPPORT
static int write_bpf_prog_info(struct feat_fd *ff,
struct evlist *evlist __maybe_unused)
diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h
index c9e3265832d9..0eb4bc29a5a4 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -158,6 +158,7 @@ int do_write(struct feat_fd *fd, const void *buf, size_t size);
int write_padded(struct feat_fd *fd, const void *bf,
size_t count, size_t count_aligned);
+int is_cpu_online(unsigned int cpu);
/*
* arch specific callback
*/