1 files changed, 89 insertions, 0 deletions
diff --git a/tests/lib/test_heavy.c b/tests/lib/test_heavy.c
new file mode 100644
index 0000000..1e56940
--- /dev/null
+++ b/tests/lib/test_heavy.c
@@ -0,0 +1,89 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ */
+
+/* This programme shows the effects of 'heavy' long-running functions
+ * on the cooperative threading model.
+ *
+ * Run it with a config file containing 'password whatever', telnet to it
+ * (it defaults to port 4000) and enter the 'clear foo string' command.
+ * then type whatever and observe that the vty interface is unresponsive
+ * for quite a period of time, due to the clear_something command
+ * taking a very long time to complete.
+ */
+#include <zebra.h>
+
+#include "frrevent.h"
+#include "vty.h"
+#include "command.h"
+#include "memory.h"
+#include <math.h>
+
+#include "tests.h"
+
+enum { ITERS_FIRST = 0,
+       ITERS_ERR = 100,
+       ITERS_LATER = 400,
+       ITERS_PRINT = 10,
+       ITERS_MAX = 1000,
+};
+
+static void slow_func(struct vty *vty, const char *str, const int i)
+{
+	double x = 1;
+	int j;
+
+	for (j = 0; j < 300; j++)
+		x += sin(x) * j;
+
+	if ((i % ITERS_LATER) == 0)
+		printf("%s: %d, temporary error, save this somehow and do it later..\n",
+		       __func__, i);
+
+	if ((i % ITERS_ERR) == 0)
+		printf("%s: hard error\n", __func__);
+
+	if ((i % ITERS_PRINT) == 0)
+		printf("%s did %d, x = %g\n", str, i, x);
+}
+
+static void clear_something(struct vty *vty, const char *str)
+{
+	int i;
+
+	/* this could be like iterating through 150k of route_table
+	 * or worse, iterating through a list of peers, to bgp_stop them with
+	 * each having 150k route tables to process...
+	 */
+	for (i = ITERS_FIRST; i < ITERS_MAX; i++)
+		slow_func(vty, str, i);
+}
+
+DEFUN (clear_foo,
+       clear_foo_cmd,
+       "clear foo LINE...",
+       "clear command\n"
+       "arbitrary string\n")
+{
+	char *str;
+	if (!argc) {
+		vty_out(vty, "%% string argument required\n");
+		return CMD_WARNING;
+	}
+
+	str = argv_concat(argv, argc, 0);
+
+	clear_something(vty, str);
+	XFREE(MTYPE_TMP, str);
+	return CMD_SUCCESS;
+}
+
+static void slow_vty_init(void)
+{
+	install_element(VIEW_NODE, &clear_foo_cmd);
+}
+
+void test_init(void)
+{
+	slow_vty_init();
+}