perf bench: Share some global variables to fix build with gcc 10

ANBZ: torvalds#668

commit e4d9b04 upstream.

Noticed with gcc 10 (fedora rawhide) that those variables were not being
declared as static, so end up with:

  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `end'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `start'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-wait.o:/git/perf/tools/perf/bench/epoll-wait.c:93: multiple definition of `runtime'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `end'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `start'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  ld: /tmp/build/perf/bench/epoll-ctl.o:/git/perf/tools/perf/bench/epoll-ctl.c:38: multiple definition of `runtime'; /tmp/build/perf/bench/futex-hash.o:/git/perf/tools/perf/bench/futex-hash.c:40: first defined here
  make[4]: *** [/git/perf/tools/build/Makefile.build:145: /tmp/build/perf/bench/perf-in.o] Error 1

Prefix those with bench__ and add them to bench/bench.h, so that we can
share those on the tools needing to access those variables from signal
handlers.

Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lore.kernel.org/lkml/20200303155811.GD13702@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com>
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>

tools/perf/bench/bench.h

@@ -2,6 +2,10 @@
 #ifndef BENCH_H
 #define BENCH_H
 
+#include <sys/time.h>
+
+extern struct timeval bench__start, bench__end, bench__runtime;
+
 /*
  * The madvise transparent hugepage constants were added in glibc
  * 2.13. For compatibility with older versions of glibc, define these

tools/perf/bench/futex-hash.c

@@ -35,7 +35,7 @@ static unsigned int nfutexes = 1024;
 static bool fshared = false, done = false, silent = false;
 static int futex_flag = 0;
 
-struct timeval start, end, runtime;
+struct timeval bench__start, bench__end, bench__runtime;
 static pthread_mutex_t thread_lock;
 static unsigned int threads_starting;
 static struct stats throughput_stats;
@@ -101,8 +101,8 @@ static void toggle_done(int sig __maybe_unused,
 {
 	/* inform all threads that we're done for the day */
 	done = true;
-	gettimeofday(&end, NULL);
-	timersub(&end, &start, &runtime);
+	gettimeofday(&bench__end, NULL);
+	timersub(&bench__end, &bench__start, &bench__runtime);
 }
 
 static void print_summary(void)
@@ -112,7 +112,7 @@ static void print_summary(void)
 
 	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
 	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
-	       (int) runtime.tv_sec);
+	       (int)bench__runtime.tv_sec);
 }
 
 int bench_futex_hash(int argc, const char **argv)
@@ -159,7 +159,7 @@ int bench_futex_hash(int argc, const char **argv)
 
 	threads_starting = nthreads;
 	pthread_attr_init(&thread_attr);
-	gettimeofday(&start, NULL);
+	gettimeofday(&bench__start, NULL);
 	for (i = 0; i < nthreads; i++) {
 		worker[i].tid = i;
 		worker[i].futex = calloc(nfutexes, sizeof(*worker[i].futex));
@@ -202,7 +202,7 @@ int bench_futex_hash(int argc, const char **argv)
 	pthread_mutex_destroy(&thread_lock);
 
 	for (i = 0; i < nthreads; i++) {
-		unsigned long t = worker[i].ops/runtime.tv_sec;
+		unsigned long t = worker[i].ops / bench__runtime.tv_sec;
 		update_stats(&throughput_stats, t);
 		if (!silent) {
 			if (nfutexes == 1)

tools/perf/bench/futex-lock-pi.c

@@ -35,7 +35,6 @@ static bool silent = false, multi = false;
 static bool done = false, fshared = false;
 static unsigned int nthreads = 0;
 static int futex_flag = 0;
-struct timeval start, end, runtime;
 static pthread_mutex_t thread_lock;
 static unsigned int threads_starting;
 static struct stats throughput_stats;
@@ -62,7 +61,7 @@ static void print_summary(void)
 
 	printf("%sAveraged %ld operations/sec (+- %.2f%%), total secs = %d\n",
 	       !silent ? "\n" : "", avg, rel_stddev_stats(stddev, avg),
-	       (int) runtime.tv_sec);
+	       (int)bench__runtime.tv_sec);
 }
 
 static void toggle_done(int sig __maybe_unused,
@@ -71,8 +70,8 @@ static void toggle_done(int sig __maybe_unused,
 {
 	/* inform all threads that we're done for the day */
 	done = true;
-	gettimeofday(&end, NULL);
-	timersub(&end, &start, &runtime);
+	gettimeofday(&bench__end, NULL);
+	timersub(&bench__end, &bench__start, &bench__runtime);
 }
 
 static void *workerfn(void *arg)
@@ -183,7 +182,7 @@ int bench_futex_lock_pi(int argc, const char **argv)
 
 	threads_starting = nthreads;
 	pthread_attr_init(&thread_attr);
-	gettimeofday(&start, NULL);
+	gettimeofday(&bench__start, NULL);
 
 	create_threads(worker, thread_attr, cpu);
 	pthread_attr_destroy(&thread_attr);
@@ -209,7 +208,7 @@ int bench_futex_lock_pi(int argc, const char **argv)
 	pthread_mutex_destroy(&thread_lock);
 
 	for (i = 0; i < nthreads; i++) {
-		unsigned long t = worker[i].ops/runtime.tv_sec;
+		unsigned long t = worker[i].ops / bench__runtime.tv_sec;
 
 		update_stats(&throughput_stats, t);
 		if (!silent)