[PATCH 2/5] trace-cmd: Use tracing directory to count CPUs
STALE5156d
From: Yoshihiro YUNOMAE <hidden>
Date: 2012-08-22 08:43:39
Also in:
lkml, qemu-devel
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Masami Hiramatsu <redacted> Count debugfs/tracing/per_cpu/cpu* to determine the number of CPUs. Signed-off-by: Masami Hiramatsu <redacted> Signed-off-by: Yoshihiro YUNOMAE <redacted> --- trace-record.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/trace-record.c b/trace-record.c
index 9dc18a9..ed18951 100644
--- a/trace-record.c
+++ b/trace-record.c@@ -1179,6 +1179,41 @@ static void expand_event_list(void) } } +static int count_tracingdir_cpus(void) +{ + char *tracing_dir = NULL; + char *percpu_dir = NULL; + struct dirent **namelist; + int count = 0, n; + + /* Count cpus in per_cpu directory */ + tracing_dir = tracecmd_find_tracing_dir(); + if (!tracing_dir) + return 0; + percpu_dir = malloc_or_die(strlen(tracing_dir) + 9); + if (!percpu_dir) + goto err; + + sprintf(percpu_dir, "%s/per_cpu", tracing_dir); + + n = scandir(percpu_dir, &namelist, NULL, alphasort); + if (n > 0) { + while (n--) { + if (strncmp("cpu", namelist[n]->d_name, 3) == 0) + count++; + free(namelist[n]); + } + free(namelist); + } + + if (percpu_dir) + free(percpu_dir); +err: + if (tracing_dir) + free(tracing_dir); + return count; +} + static int count_cpus(void) { FILE *fp;
@@ -1189,6 +1224,12 @@ static int count_cpus(void) size_t n; int r; + cpus = count_tracingdir_cpus(); + if (cpus > 0) + return cpus; + + warning("failed to use tracing_dir to determine number of CPUS"); + cpus = sysconf(_SC_NPROCESSORS_CONF); if (cpus > 0) return cpus;