[PATCH v2 2/8] perf header: Move is_cpu_online to numa bench

Ian Rogers
2024-11-07T16:34:12Z

The helper function is only used in the NUMA benchmark as typically
online CPUs are determined through
perf_cpu_map__new_online_cpus(). Reduce the scope of the function for
now.

Signed-off-by: Ian Rogers <irogers@google.com>
---
tools/perf/bench/numa.c | 53 ++++++++++++++++++++++++++++++++++++++++
tools/perf/util/header.c | 51 --------------------------------------
tools/perf/util/header.h | 1 -
3 files changed, 53 insertions(+), 52 deletions(-)

diff --git a/tools/perf/bench/numa.c b/tools/perf/bench/numa.c
index 1fbd7c947abc..19be2aaf4dc0 100644
--- a/tools/perf/bench/numa.c
+++ b/tools/perf/bench/numa.c
@@ -27,6 +27,7 @@
#include <sys/resource.h>
#include <sys/wait.h>
#include <sys/prctl.h>
+#include <sys/stat.h>
#include <sys/types.h>
#include <linux/kernel.h>
#include <linux/time64.h>
@@ -35,6 +36,7 @@

#include "../util/header.h"
#include "../util/mutex.h"
+#include <api/fs/fs.h>
#include <numa.h>
#include <numaif.h>

@@ -533,6 +535,57 @@ static int parse_cpu_list(const char *arg)
return 0;
}

+/*
+ * Check whether a CPU is online
+ *
+ * Returns:
+ * 1 -> if CPU is online
+ * 0 -> if CPU is offline
+ * -1 -> error case
+ */
+static 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;
+}
+
static int parse_setup_cpu_list(void)
{
struct thread_data *td;
diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
index a6386d12afd7..55c28e4377ec 100644
--- a/tools/perf/util/header.c
+++ b/tools/perf/util/header.c
@@ -987,57 +987,6 @@ 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 a63a361f20f4..e91e89d22537 100644
--- a/tools/perf/util/header.h
+++ b/tools/perf/util/header.h
@@ -196,7 +196,6 @@ int write_padded(struct feat_fd *fd, const void *bf,

#define MAX_CACHE_LVL 4

-int is_cpu_online(unsigned int cpu);
int build_caches_for_cpu(u32 cpu, struct cpu_cache_level caches[], u32 *cntp);

/*