From 7bcbb1f6534713a915ad4d1ac2e8ac0523937920 Mon Sep 17 00:00:00 2001
From: Jef Poskanzer <jef@mail.acme.com>
Date: Fri, 15 Nov 2013 09:54:21 -0800
Subject: [PATCH] Performance improvements.

---
 src/iperf_api.c        |  7 +++++--
 src/iperf_client_api.c | 18 ++++++++++--------
 src/iperf_server_api.c | 15 ++++++++++-----
 3 files changed, 25 insertions(+), 15 deletions(-)

diff --git a/src/iperf_api.c b/src/iperf_api.c
index f2ccfbf..48a8b37 100644
--- a/src/iperf_api.c
+++ b/src/iperf_api.c
@@ -772,10 +772,13 @@ iperf_check_throttle(struct iperf_stream *sp, struct timeval *nowP)
 
     seconds = timeval_diff(&sp->result->start_time, nowP);
     bits_per_second = sp->result->bytes_sent * 8 / seconds;
-    if (bits_per_second < sp->test->settings->rate)
+    if (bits_per_second < sp->test->settings->rate) {
         sp->green_light = 1;
-    else
+        FD_SET(sp->socket, &sp->test->write_set);
+    } else {
         sp->green_light = 0;
+        FD_CLR(sp->socket, &sp->test->write_set);
+    }
 }
 
 int
diff --git a/src/iperf_client_api.c b/src/iperf_client_api.c
index 2178a29..18cf8fa 100644
--- a/src/iperf_client_api.c
+++ b/src/iperf_client_api.c
@@ -319,9 +319,10 @@ iperf_run_client(struct iperf_test * test)
     int startup;
 #define CM_SELECT 1
 #define CM_SIGALRM 2
-    int result;
+    int result = 0;
     fd_set read_set, write_set;
     struct timeval now;
+    struct timeval* timeout = NULL;
 
     /* Termination signals. */
     iperf_catch_sigend(sigend_handler);
@@ -355,13 +356,14 @@ iperf_run_client(struct iperf_test * test)
 
     startup = 1;
     concurrency_model = CM_SELECT;	/* always start in select mode */
-    (void) gettimeofday(&now, NULL);
     while (test->state != IPERF_DONE) {
 
 	if (concurrency_model == CM_SELECT) {
 	    memcpy(&read_set, &test->read_set, sizeof(fd_set));
 	    memcpy(&write_set, &test->write_set, sizeof(fd_set));
-	    result = select(test->max_fd + 1, &read_set, &write_set, NULL, tmr_timeout(&now));
+	    (void) gettimeofday(&now, NULL);
+	    timeout = tmr_timeout(&now);
+	    result = select(test->max_fd + 1, &read_set, &write_set, NULL, timeout);
 	    if (result < 0 && errno != EINTR) {
 		i_errno = IESELECT;
 		return -1;
@@ -402,17 +404,17 @@ iperf_run_client(struct iperf_test * test)
 
 	    if (test->reverse) {
 		// Reverse mode. Client receives.
-		if (iperf_recv(test, &read_set) < 0) {
+		if (iperf_recv(test, &read_set) < 0)
 		    return -1;
-		}
 	    } else {
 		// Regular mode. Client sends.
-		if (iperf_send(test, concurrency_model == CM_SIGALRM ? NULL : &write_set) < 0) {
+		if (iperf_send(test, concurrency_model == CM_SIGALRM ? NULL : &write_set) < 0)
 		    return -1;
-		}
 	    }
 
-	    if (concurrency_model == CM_SELECT ||
+	    if ((concurrency_model == CM_SELECT &&
+	         (result == 0 ||
+		  (timeout != NULL && timeout->tv_sec == 0 && timeout->tv_usec == 0))) ||
 	        (concurrency_model == CM_SIGALRM && sigalrm_triggered)) {
 		/* Run the timers. */
 		(void) gettimeofday(&now, NULL);
diff --git a/src/iperf_server_api.c b/src/iperf_server_api.c
index 9fb52d1..d5ec537 100644
--- a/src/iperf_server_api.c
+++ b/src/iperf_server_api.c
@@ -417,6 +417,7 @@ iperf_run_server(struct iperf_test *test)
     fd_set read_set, write_set;
     struct iperf_stream *sp;
     struct timeval now;
+    struct timeval* timeout;
 
     /* Termination signals. */
     iperf_catch_sigend(sigend_handler);
@@ -452,13 +453,14 @@ iperf_run_server(struct iperf_test *test)
     test->state = IPERF_START;
     streams_accepted = 0;
 
-    (void) gettimeofday(&now, NULL);
     while (test->state != IPERF_DONE) {
 
         memcpy(&read_set, &test->read_set, sizeof(fd_set));
         memcpy(&write_set, &test->write_set, sizeof(fd_set));
 
-        result = select(test->max_fd + 1, &read_set, &write_set, NULL, tmr_timeout(&now));
+	(void) gettimeofday(&now, NULL);
+	timeout = tmr_timeout(&now);
+        result = select(test->max_fd + 1, &read_set, &write_set, NULL, timeout);
         if (result < 0 && errno != EINTR) {
 	    cleanup_server(test);
             i_errno = IESELECT;
@@ -570,9 +572,12 @@ iperf_run_server(struct iperf_test *test)
 		    }
                 }
 
-		/* Run the timers. */
-		(void) gettimeofday(&now, NULL);
-		tmr_run(&now);
+		if (result == 0 ||
+		    (timeout != NULL && timeout->tv_sec == 0 && timeout->tv_usec == 0)) {
+		    /* Run the timers. */
+		    (void) gettimeofday(&now, NULL);
+		    tmr_run(&now);
+		}
             }
         }
     }