diff --git a/src/dnsperf.c b/src/dnsperf.c
index 8c731be..f124f64 100644
--- a/src/dnsperf.c
+++ b/src/dnsperf.c
@@ -853,6 +853,40 @@ wait_for_start(void)
     PERF_UNLOCK(&start_lock);
 }
 
+static inline void
+bit_set(unsigned char* bits, unsigned int bit)
+{
+    unsigned int shift, mask;
+
+    shift = 7 - (bit % 8);
+    mask  = 1 << shift;
+
+    bits[bit / 8] |= mask;
+}
+
+static inline void
+bit_clear(unsigned char* bits, unsigned int bit)
+{
+    unsigned int shift, mask;
+
+    shift = 7 - (bit % 8);
+    mask  = 1 << shift;
+
+    bits[bit / 8] &= ~mask;
+}
+
+static inline bool
+bit_check(unsigned char* bits, unsigned int bit)
+{
+    unsigned int shift;
+
+    shift = 7 - (bit % 8);
+
+    if ((bits[bit / 8] >> shift) & 0x01)
+        return true;
+    return false;
+}
+
 static void*
 do_send(void* arg)
 {
@@ -871,9 +905,10 @@ do_send(void* arg)
     unsigned char   packet_buffer[MAX_EDNS_PACKET];
     unsigned char*  base;
     unsigned int    length;
-    int             n, i, any_inprogress = 0;
+    int             n, i, any_inprogress = 0, sock = 0;
     perf_result_t   result;
     bool            all_fail;
+    unsigned char   socketbits[(MAX_SOCKETS / 8) + 1] = {};
 
     tinfo           = (threadinfo_t*)arg;
     config          = tinfo->config;
@@ -904,8 +939,13 @@ do_send(void* arg)
         if (any_inprogress) {
             any_inprogress = 0;
             for (i = 0; i < tinfo->nsocks; i++) {
+                if (!bit_check(socketbits, i)) {
+                    continue;
+                }
                 if (!perf_net_sockready(tinfo->socks[i], threadpipe[0], TIMEOUT_CHECK_TIME)) {
                     any_inprogress = 1;
+                } else {
+                    bit_clear(socketbits, i);
                 }
             }
         }
@@ -980,7 +1020,8 @@ do_send(void* arg)
         i        = tinfo->nsocks * 2;
         all_fail = true;
         while (i--) {
-            q->sock = tinfo->socks[tinfo->current_sock++ % tinfo->nsocks];
+            sock    = tinfo->current_sock++ % tinfo->nsocks;
+            q->sock = tinfo->socks[sock];
             switch (perf_net_sockready(q->sock, threadpipe[0], TIMEOUT_CHECK_TIME)) {
             case 0:
                 if (config->verbose && !config->suppress.sockready) {
@@ -1076,6 +1117,7 @@ do_send(void* arg)
                     perf_log_warning("network congested, packet sending in progress");
                 }
                 any_inprogress = 1;
+                bit_set(socketbits, sock);
             } else {
                 if (config->verbose && !config->suppress.sendfailed) {
                     char __s[256];
@@ -1201,29 +1243,6 @@ recv_one(threadinfo_t* tinfo, int which_sock,
     return true;
 }
 
-static inline void
-bit_set(unsigned char* bits, unsigned int bit)
-{
-    unsigned int shift, mask;
-
-    shift = 7 - (bit % 8);
-    mask  = 1 << shift;
-
-    bits[bit / 8] |= mask;
-}
-
-static inline bool
-bit_check(unsigned char* bits, unsigned int bit)
-{
-    unsigned int shift;
-
-    shift = 7 - (bit % 8);
-
-    if ((bits[bit / 8] >> shift) & 0x01)
-        return true;
-    return false;
-}
-
 static void*
 do_recv(void* arg)
 {
@@ -1233,7 +1252,7 @@ do_recv(void* arg)
     received_query_t recvd[RECV_BATCH_SIZE] = { { 0, 0, 0, 0, 0, 0, false, false, 0 } };
     unsigned int     nrecvd;
     int              saved_errno;
-    unsigned char    socketbits[MAX_SOCKETS / 8];
+    unsigned char    socketbits[(MAX_SOCKETS / 8) + 1];
     uint64_t         now, latency;
     query_info*      q;
     unsigned int     current_socket, last_socket;
@@ -1656,8 +1675,7 @@ int main(int argc, char** argv)
     perf_os_handlesignal(SIGINT, handle_sigint);
     perf_os_blocksignal(SIGINT, false);
     sock.fd = mainpipe[0];
-    result  = perf_os_waituntilreadable(&sock, intrpipe[0],
-        times.stop_time - times.start_time);
+    result  = perf_os_waituntilreadable(&sock, intrpipe[0], times.stop_time - times.start_time);
     if (result == PERF_R_CANCELED)
         interrupted = true;