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perf tools: Add perf_event_paranoid()

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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>
This commit is contained in:
Adrian Hunter 2013-12-11 14:36:23 +02:00 committed by Arnaldo Carvalho de Melo
parent c506c96b61
commit 1a47245d2f
3 changed files with 21 additions and 2 deletions
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3
tools/perf/util/evlist.c
View File

@ -1191,8 +1191,7 @@ int perf_evlist__strerror_open(struct perf_evlist *evlist __maybe_unused,
"Error:\t%s.\n"
"Hint:\tCheck /proc/sys/kernel/perf_event_paranoid setting.", emsg);
if (filename__read_int("/proc/sys/kernel/perf_event_paranoid", &value))
break;
value = perf_event_paranoid();
printed += scnprintf(buf + printed, size - printed, "\nHint:\t");

19
tools/perf/util/util.c
View File

@ -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 @@ const char *get_filename_for_perf_kvm(void)
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;
}

1
tools/perf/util/util.h
View File

@ -321,6 +321,7 @@ void free_srcline(char *srcline);
int filename__read_int(const char *filename, int *value);
int filename__read_str(const char *filename, char **buf, size_t *sizep);
int perf_event_paranoid(void);
const char *get_filename_for_perf_kvm(void);
#endif /* GIT_COMPAT_UTIL_H */