main-loop: partial revert of 5e3bc73

This patch reverts part of 5e3bc735d93dd23f074b5116fd11e1ad8cd4962f.

Paolo Bonzini wrote this patch and commented:

"WSAEventSelect is edge-triggered and the event will not be signaled if
the socket handler does not consume all the data in the socket buffer."

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-id: 1368718561-7816-3-git-send-email-stefanha@redhat.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

diff --git a/main-loop.c b/main-loop.c
index 2b8eed7311b6f7fdbf487c016f35ec72fd438aff..cf36645af482cf1d60799c107dc5fab02701b8aa 100644 (file)
--- a/main-loop.c
+++ b/main-loop.c
@@ -394,6 +394,20 @@ static int os_host_main_loop_wait(uint32_t timeout)
         return ret;
     }
 
+    FD_ZERO(&rfds);
+    FD_ZERO(&wfds);
+    FD_ZERO(&xfds);
+    nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
+    if (nfds >= 0) {
+        select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
+        if (select_ret != 0) {
+            timeout = 0;
+        }
+        if (select_ret > 0) {
+            pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
+        }
+    }
+
     g_main_context_prepare(context, &max_priority);
     n_poll_fds = g_main_context_query(context, max_priority, &poll_timeout,
                                       poll_fds, ARRAY_SIZE(poll_fds));
@@ -426,24 +440,6 @@ static int os_host_main_loop_wait(uint32_t timeout)
         g_main_context_dispatch(context);
     }
 
-    /* Call select after g_poll to avoid a useless iteration and therefore
-     * improve socket latency.
-     */
-
-    FD_ZERO(&rfds);
-    FD_ZERO(&wfds);
-    FD_ZERO(&xfds);
-    nfds = pollfds_fill(gpollfds, &rfds, &wfds, &xfds);
-    if (nfds >= 0) {
-        select_ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv0);
-        if (select_ret != 0) {
-            timeout = 0;
-        }
-        if (select_ret > 0) {
-            pollfds_poll(gpollfds, nfds, &rfds, &wfds, &xfds);
-        }
-    }
-
     return select_ret || g_poll_ret;
 }
 #endif