test/emu/ovni/CMakeLists.txt

@@ -11,6 +11,7 @@ test_emu(sort-first-and-full-ring.c SORT
   SHOULD_FAIL REGEX "cannot find a event previous to clock")
 test_emu(burst-stats.c REGEX "burst stats: median/avg/max =  33/ 33/ 33 ns")
 test_emu(mp-simple.c MP)
+test_emu(merge-cpus-loom.c MP)
 test_emu(version-good.c)
 test_emu(version-bad.c SHOULD_FAIL REGEX "incompatible .* version")
 test_emu(clockgate.c MP SHOULD_FAIL REGEX "detected large clock gate")

test/emu/ovni/merge-cpus-loom.c

@@ -0,0 +1,52 @@
+/* Copyright (c) 2024 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include <stdlib.h>
+#include "compat.h"
+#include "instr.h"
+
+/* Ensure we can emit CPUs from multiple threads of the same loom */
+
+static inline void
+start(int rank, int nranks)
+{
+	char hostname[OVNI_MAX_HOSTNAME];
+
+	if (gethostname(hostname, OVNI_MAX_HOSTNAME) != 0)
+		die("gethostname failed");
+
+	ovni_version_check();
+
+	/* Only one loom */
+	ovni_proc_init(1, hostname, getpid());
+	ovni_proc_set_rank(rank, nranks);
+	ovni_thread_init(get_tid());
+
+	/* Only emit a subset of CPUs up to the rank number */
+	for (int i = 0; i <= rank; i++)
+		ovni_add_cpu(i, i);
+
+	int curcpu = rank;
+
+	dbg("thread %d has cpu %d (ncpus=%d)",
+			get_tid(), curcpu, nranks);
+
+	instr_require("ovni");
+	instr_thread_execute(curcpu, -1, 0);
+}
+
+
+int
+main(void)
+{
+	int rank = atoi(getenv("OVNI_RANK"));
+	int nranks = atoi(getenv("OVNI_NRANKS"));
+
+	start(rank, nranks);
+
+	sleep_us(50 * 1000);
+
+	instr_end();
+
+	return 0;
+}