bench: skip oversized pool cases based on fd budget

Author: pawelzelawski

bench/bench_checkout.c

@@ -11,6 +11,7 @@
 static int
 run_case(uint32_t pool_size, uint32_t iterations)
 {
+	uint32_t fd_budget;
 	pid_t server_pid = -1;
 	uint16_t port = 0;
 	int event_fd = -1;
@@ -23,6 +24,14 @@ run_case(uint32_t pool_size, uint32_t iterations)
 	int err = 0;
 	int rc = 0;
 
+	fd_budget = bench_fd_budget();
+	if (pool_size > fd_budget) {
+		printf("checkout with immediate connection (pool size %u): "
+		       "skipped (fd budget %u)\n",
+		       pool_size, fd_budget);
+		return 0;
+	}
+
 	if (bench_start_server(&server_pid, &port) != BRAID_OK)
 		return 1;
 

bench/bench_common.c

@@ -7,6 +7,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <sys/resource.h>
 #include <sys/socket.h>
 #include <sys/types.h>
 #include <sys/utsname.h>
@@ -285,6 +286,27 @@ bench_pool_idle_count(braid_pool_t *pool)
 	return count;
 }
 
+uint32_t
+bench_fd_budget(void)
+{
+	struct rlimit lim;
+	const rlim_t reserve = (rlim_t)64;
+
+	if (getrlimit(RLIMIT_NOFILE, &lim) != 0)
+		return UINT32_MAX;
+
+	if (lim.rlim_cur == RLIM_INFINITY)
+		return UINT32_MAX;
+
+	if (lim.rlim_cur <= reserve)
+		return 0;
+
+	if (lim.rlim_cur - reserve > (rlim_t)UINT32_MAX)
+		return UINT32_MAX;
+
+	return (uint32_t)(lim.rlim_cur - reserve);
+}
+
 int
 bench_warm_pool(braid_pool_t *pool, int event_fd, uint32_t want_idle,
 		int max_steps)

bench/bench_common.h

@@ -24,6 +24,7 @@ int bench_start_server(pid_t *pid_out, uint16_t *port_out);
 void bench_stop_server(pid_t pid);
 int bench_event_loop_step(braid_pool_t *pool, int event_fd, int max_wait_ms);
 uint32_t bench_pool_idle_count(braid_pool_t *pool);
+uint32_t bench_fd_budget(void);
 int bench_warm_pool(braid_pool_t *pool, int event_fd, uint32_t want_idle,
 		    int max_steps);
 void bench_print_hw_context(const char *name);

bench/bench_pool_scale.c

@@ -11,6 +11,7 @@
 static int
 run_case(uint32_t pool_size, uint32_t operations)
 {
+	uint32_t fd_budget;
 	pid_t server_pid = -1;
 	uint16_t port = 0;
 	int event_fd = -1;
@@ -23,6 +24,14 @@ run_case(uint32_t pool_size, uint32_t operations)
 	int err = 0;
 	int rc = 0;
 
+	fd_budget = bench_fd_budget();
+	if (pool_size > fd_budget) {
+		printf("pool scale (max_connections=%u): "
+		       "skipped (fd budget %u)\n",
+		       pool_size, fd_budget);
+		return 0;
+	}
+
 	if (bench_start_server(&server_pid, &port) != BRAID_OK)
 		return 1;