perf tools: Add perf_event_paranoid()
Add a function to return the value of
/proc/sys/kernel/perf_event_paranoid.
This will be used to determine default values for mmap size because perf
is not subject to mmap limits when perf_event_paranoid is less than
zero.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1386765443-26966-12-git-send-email-alexander.shishkin@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/util.c b/tools/perf/util/util.c
index 4a57609..8f63dba 100644
--- a/tools/perf/util/util.c
+++ b/tools/perf/util/util.c
@@ -1,5 +1,6 @@
#include "../perf.h"
#include "util.h"
+#include "fs.h"
#include <sys/mman.h>
#ifdef HAVE_BACKTRACE_SUPPORT
#include <execinfo.h>
@@ -8,6 +9,7 @@
#include <stdlib.h>
#include <string.h>
#include <errno.h>
+#include <limits.h>
#include <linux/kernel.h>
/*
@@ -496,3 +498,20 @@
return filename;
}
+
+int perf_event_paranoid(void)
+{
+ char path[PATH_MAX];
+ const char *procfs = procfs__mountpoint();
+ int value;
+
+ if (!procfs)
+ return INT_MAX;
+
+ scnprintf(path, PATH_MAX, "%s/sys/kernel/perf_event_paranoid", procfs);
+
+ if (filename__read_int(path, &value))
+ return INT_MAX;
+
+ return value;
+}