[PATCH] blktrace: sendfile() improvements

diff --git a/blktrace.c b/blktrace.c
index 39280ca15d6808fce2a70c92c5c46c5da868ddee..071a6b274477f6e92f0c457fa768fb6e1dbd4af8 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -290,7 +290,7 @@ enum {
 static char hostname[MAXHOSTNAMELEN];
 static int net_port = TRACE_NET_PORT;
 static int net_mode = 0;
-static int net_sendfile;
+static int net_use_sendfile;
 
 static int net_in_fd = -1;
 static int net_out_fd = -1;
@@ -704,7 +704,7 @@ static void *thread_main(void *arg)
                exit_trace(1);
        }
 
-       if (net_mode == Net_client && net_sendfile) {
+       if (net_mode == Net_client && net_use_sendfile) {
                char tmp[MAXPATHLEN + 64];
 
                snprintf(tmp, sizeof(tmp), "%s/block/%s/trace%d.padding",
@@ -795,12 +795,33 @@ static int flush_subbuf_net(struct thread_information *tip,
        return 0;
 }
 
+static int net_sendfile(struct thread_information *tip, struct tip_subbuf *ts)
+{
+       unsigned int bytes_left = ts->len;
+       int ret;
+
+       while (bytes_left && is_done()) {
+               ret = sendfile(net_out_fd, tip->fd, &ts->offset, bytes_left);
+               if (ret < 0) {
+                       perror("sendfile");
+                       break;
+               } else if (!ret) {
+                       usleep(100);
+                       continue;
+               }
+
+               ts->offset += ret;
+               bytes_left -= ret;
+       }
+
+       return bytes_left;
+}
+
 static int flush_subbuf_sendfile(struct thread_information *tip,
                                 struct tip_subbuf *ts)
 {
        size_t padding;
        unsigned subbuf;
-       unsigned len;
 
        /*
         * currently we cannot use sendfile() on the last bytes read, as they
@@ -812,16 +833,14 @@ static int flush_subbuf_sendfile(struct thread_information *tip,
        
        subbuf = (ts->offset / buf_size) % buf_nr;
        padding = get_subbuf_padding(tip, subbuf);
-       len = ts->len - padding;
+       ts->len -= padding;
 
-       if (net_send_header(tip, len))
+       if (net_send_header(tip, ts->len))
                return 1;
-       if (sendfile(net_out_fd, tip->fd, &ts->offset, len) < 0) {
-               perror("sendfile");
+       if (net_sendfile(tip, ts))
                return 1;
-       }
 
-       tip->data_read += len;
+       tip->data_read += ts->len;
        free(ts);
        return 0;
 }
@@ -1665,7 +1684,7 @@ int main(int argc, char *argv[])
                        net_port = atoi(optarg);
                        break;
                case 's':
-                       net_sendfile = 1;
+                       net_use_sendfile = 1;
                        break;
                default:
                        show_usage(argv[0]);