perf tools: Fallback to reading sysfs to get cacheline size

On systems where sysconf(_SC_LEVEL1_DCACHE_LINESIZE) is not available,
such as musl LIBC and Android's bionic libc.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Chris Phlipot <cphlipot0@gmail.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-772obxzby758g7m2wmzcejxz@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 11 insertions, 1 deletions

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
index f7d7dbbd2af6..4b2ff021434c 100644
--- a/tools/perf/perf.c
+++ b/tools/perf/perf.c
@@ -497,6 +497,16 @@ void pthread__unblock_sigwinch(void)
         pthread_sigmask(SIG_UNBLOCK, &set, NULL);
 }
 
+#ifdef _SC_LEVEL1_DCACHE_LINESIZE
+#define cache_line_size(cacheline_sizep) *cacheline_sizep = sysconf(_SC_LEVEL1_DCACHE_LINESIZE)
+#else
+static void cache_line_size(int *cacheline_sizep)
+{
+        if (sysfs__read_int("devices/system/cpu/cpu0/cache/index0/coherency_line_size", cacheline_sizep))
+                perror("cannot determine cache line size");
+}
+#endif
+
 int main(int argc, const char **argv)
 {
         const char *cmd;
@@ -509,7 +519,7 @@ int main(int argc, const char **argv)
 
         /* The page_size is placed in util object. */
         page_size = sysconf(_SC_PAGE_SIZE);
-        cacheline_size = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);
+        cache_line_size(&cacheline_size);
 
         if (sysctl__read_int("kernel/perf_event_max_stack", &value) == 0)
                 sysctl_perf_event_max_stack = value;