Add burst stats test

test/emu/ovni/CMakeLists.txt

@@ -11,5 +11,6 @@ ovni_test(sort.c SORT)
 ovni_test(empty-sort.c SORT)
 ovni_test(sort-first-and-full-ring.c SORT
   SHOULD_FAIL REGEX "cannot find a event previous to clock")
+ovni_test(burst-stats.c REGEX "burst stats: median 33 ns, avg 33\.0 ns, max 33 ns")
 ovni_test(mp-simple.c MP)
 ovni_test(mp-rank.c MP)

test/emu/ovni/burst-stats.c

@@ -0,0 +1,49 @@
+/* Copyright (c) 2021-2022 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#define _POSIX_C_SOURCE 200112L
+#define _GNU_SOURCE
+
+#include <limits.h>
+#include <linux/limits.h>
+#include <stddef.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <sys/syscall.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include "compat.h"
+#include "ovni.h"
+#include "../instr.h"
+
+static void
+emit(char *mcv, uint64_t clock)
+{
+	struct ovni_ev ev = {0};
+	ovni_ev_set_mcv(&ev, mcv);
+	ovni_ev_set_clock(&ev, clock);
+	ovni_ev_emit(&ev);
+}
+
+int
+main(void)
+{
+	instr_start(0, 1);
+
+	uint64_t t = ovni_clock_now();
+
+	/* Emit bursts with controlled clocks */
+	for (int i = 0; i < 100; i++) {
+		emit("OB.", t);
+		t += 33;
+	}
+
+	/* Sleep a bit to prevent unsorted events */
+	while (ovni_clock_now() < t)
+		usleep(10);
+
+	instr_end();
+
+	return 0;
+}