Re: [Qemu-devel] Network Performance between Win Host and Linux

[Leonardo E. Reiter]

Hi Ken,

please disregard my last mail on this... here's a current patch against 
today's CVS.  I didn't realize that vl.c already converted from poll() 
to select(), so the patch logic is much easier and cleaner.

Check it out... I tested it minimally and it seems to work - only tested 
it on Linux host,

Leo

P.S. you can apply this one with -p0 arg to patch.

Kenneth Duda wrote:
> Paul, thanks for the note.
>
> In my case, the guest CPU is idle.  The host CPU utilization is only 5
> or 10 percent when running "find / -print > /dev/null" on the guest. 
> So I don't think guest interrupt latency is the issue for me in this
> case.

--
Leonardo E. Reiter
Vice President of Product Development, CTO

Win4Lin, Inc.
Virtual Computing from Desktop to Data Center
Main: +1 512 339 7979
Fax: +1 512 532 6501
http://www.win4lin.com

Index: vl.c
===================================================================
RCS file: /cvsroot/qemu/qemu/vl.c,v
retrieving revision 1.168
diff -a -u -r1.168 vl.c
--- vl.c        9 Apr 2006 01:32:52 -0000       1.168
+++ vl.c        11 Apr 2006 20:56:56 -0000
@@ -3952,8 +3952,11 @@
 void main_loop_wait(int timeout)
 {
     IOHandlerRecord *ioh, *ioh_next;
-    fd_set rfds, wfds;
+    fd_set rfds, wfds, xfds;
     int ret, nfds;
+#if defined(CONFIG_SLIRP)
+    int slirp_nfds;
+#endif
     struct timeval tv;
 
 #ifdef _WIN32
@@ -3967,6 +3970,7 @@
     nfds = -1;
     FD_ZERO(&rfds);
     FD_ZERO(&wfds);
+    FD_ZERO(&xfds);
     for(ioh = first_io_handler; ioh != NULL; ioh = ioh->next) {
         if (ioh->fd_read &&
             (!ioh->fd_read_poll ||
@@ -3988,7 +3992,14 @@
 #else
     tv.tv_usec = timeout * 1000;
 #endif
-    ret = select(nfds + 1, &rfds, &wfds, NULL, &tv);
+#if defined(CONFIG_SLIRP)
+    if (slirp_inited) {
+        slirp_select_fill(&slirp_nfds, &rfds, &wfds, &xfds);
+        if (slirp_nfds > nfds)
+            nfds = slirp_nfds;
+    }
+#endif
+    ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
     if (ret > 0) {
         /* XXX: better handling of removal */
         for(ioh = first_io_handler; ioh != NULL; ioh = ioh_next) {
@@ -4000,30 +4011,14 @@
                 ioh->fd_write(ioh->opaque);
             }
         }
-    }
-#ifdef _WIN32
-    tap_win32_poll();
-#endif
-
 #if defined(CONFIG_SLIRP)
-    /* XXX: merge with the previous select() */
-    if (slirp_inited) {
-        fd_set rfds, wfds, xfds;
-        int nfds;
-        struct timeval tv;
-        
-        nfds = -1;
-        FD_ZERO(&rfds);
-        FD_ZERO(&wfds);
-        FD_ZERO(&xfds);
-        slirp_select_fill(&nfds, &rfds, &wfds, &xfds);
-        tv.tv_sec = 0;
-        tv.tv_usec = 0;
-        ret = select(nfds + 1, &rfds, &wfds, &xfds, &tv);
-        if (ret >= 0) {
+        if (slirp_inited)
             slirp_select_poll(&rfds, &wfds, &xfds);
-        }
+#endif
     }
+
+#ifdef _WIN32
+    tap_win32_poll();
 #endif
 
     if (vm_running) {