1 files changed, 110 insertions, 0 deletions
diff --git a/tools/perf/tests/workloads/context_switch_loop.c b/tools/perf/tests/workloads/context_switch_loop.c
new file mode 100644
index 000000000000..5431af6147e6
--- /dev/null
+++ b/tools/perf/tests/workloads/context_switch_loop.c
@@ -0,0 +1,110 @@
+
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/compiler.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/prctl.h>
+#include <sys/wait.h>
+#include <unistd.h>
+
+#include "../tests.h"
+
+static int loops = 100;
+static char buf;
+int context_switch_loop_work = 1234;
+
+#define write_block(fd) \
+	do { \
+		if (write(fd, &buf, 1) <= 0) \
+			return 1; \
+	} while (0)
+
+#define read_block(fd) \
+	do { \
+		if (read(fd, &buf, 1) <= 0) \
+			return 1; \
+	} while (0)
+
+/* Not static to avoid LTO clobbering the function name */
+int context_switch_loop_proc1(int in_fd, int out_fd);
+int context_switch_loop_proc1(int in_fd, int out_fd)
+{
+	for (int i = 0; i < loops; i++) {
+		read_block(in_fd);
+		context_switch_loop_work += i * 3;
+		write_block(out_fd);
+	}
+	return 0;
+}
+
+int context_switch_loop_proc2(int in_fd, int out_fd);
+int context_switch_loop_proc2(int in_fd, int out_fd)
+{
+	for (int i = 0; i < loops; i++) {
+		write_block(out_fd);
+		context_switch_loop_work += i * 7;
+		read_block(in_fd);
+	}
+	return 0;
+}
+
+/*
+ * Launches two processes that take turns to execute a multiplication N times
+ */
+static int context_switch_loop(int argc, const char **argv)
+{
+	int a_to_b[2], b_to_a[2];
+	pid_t proc1_pid;
+	int status;
+	int ret;
+
+	if (argc > 0) {
+		loops = atoi(argv[0]);
+		if (loops < 0) {
+			fprintf(stderr, "Invalid number of loops: %s\n", argv[0]);
+			return 1;
+		}
+	}
+
+	if (pipe(a_to_b) || pipe(b_to_a)) {
+		perror("Pipe error");
+		return 1;
+	}
+
+	proc1_pid = fork();
+	if (proc1_pid < 0) {
+		perror("Fork error");
+		return 1;
+	}
+
+	if (!proc1_pid) {
+		close(a_to_b[0]);
+		close(b_to_a[1]);
+		prctl(PR_SET_NAME, "proc1", 0, 0, 0);
+		ret = context_switch_loop_proc1(b_to_a[0], a_to_b[1]);
+		close(a_to_b[1]);
+		close(b_to_a[0]);
+		exit(ret);
+	}
+
+	close(a_to_b[1]);
+	close(b_to_a[0]);
+	prctl(PR_SET_NAME, "proc2", 0, 0, 0);
+	ret = context_switch_loop_proc2(a_to_b[0], b_to_a[1]);
+	close(a_to_b[0]);
+	close(b_to_a[1]);
+
+	if (ret) {
+		kill(proc1_pid, SIGKILL);
+		return ret;
+	}
+
+	if (waitpid(proc1_pid, &status, 0) != proc1_pid || !WIFEXITED(status) ||
+	    WEXITSTATUS(status))
+		return 1;
+
+	return 0;
+}
+
+DEFINE_WORKLOAD(context_switch_loop);