After finally getting bored with the poor performance of rsync on
Cygwin I decided to investigate.
Turns out that when using rsh or ssh as the transport, they soak up
99% of the CPU time. This is because they use non-blocking i/o, but
the Cygwin select() function incorrectly returns "ready for read or
write", even when there is no buffer space available, so they get
stuck in a loop calling select and read/write (which immediately
return EWOULDBLOCK).
The following patch fixes this problem by correctly initialising the
socket's "connect state" for rcmd/rexec sockets and socketpairs, and
then maintaining the state correctly across a fork.
Note, that this doesn't fix the other problem where rsync often hangs
at the end of a transfer. I'll look into this further when I have
time.
Nigel
--
Nigel Stephens Mailto:[EMAIL PROTECTED]
_ _ ____ ___ MIPS Technologies Phone.: +44 1223 706200
|\ /|||___)(___ The Fruit Farm Direct: +44 1223 706207
| \/ ||| ____) Ely Road, Chittering Fax...: +44 1223 706250
TECHNOLOGIES UK Cambridge CB5 9PH Cell..: +44 7976 686470
England http://www.mips.com
Index: cygwin/ChangeLog
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/ChangeLog,v
retrieving revision 1.1947
diff -u -r1.1947 ChangeLog
--- cygwin/ChangeLog 2 Jul 2003 03:50:05 -0000 1.1947
+++ cygwin/ChangeLog 3 Jul 2003 20:59:50 -0000
@@ -1,3 +1,16 @@
+Thu Jul 3 21:54:18 2003 N Stephens <[EMAIL PROTECTED]>
+
+ * net.cc (cygwin_rcmd): Mark file handles of sockets returned by
+ rcmd() as CONNECTED state.
+ (cygwin_rexec): Similarly for rexec().
+ (socketpair): Mark both ends of a new socket pair as CONNECTED.
+
+ * fhandler_socket.cc (dup): Copy socket connect state to new file
+ handle.
+
+ * fhandler.h (fhandler_socket::get_connect_state): New method to
+ return socket connection state.
+
2003-07-01 Christopher Faylor <[EMAIL PROTECTED]>
* thread.cc: Remove _MT_SAFE conditional.
Index: cygwin/fhandler.h
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/fhandler.h,v
retrieving revision 1.163
diff -u -r1.163 fhandler.h
--- cygwin/fhandler.h 26 May 2003 09:54:01 -0000 1.163
+++ cygwin/fhandler.h 3 Jul 2003 20:59:50 -0000
@@ -410,6 +410,7 @@
bool is_connect_pending () const {return had_connect_or_listen == CONNECT_PENDING;}
bool is_connected () const {return had_connect_or_listen == CONNECTED;}
void set_connect_state (int newstate) { had_connect_or_listen = newstate; }
+ int get_connect_state () const { return had_connect_or_listen; }
int bind (const struct sockaddr *name, int namelen);
int connect (const struct sockaddr *name, int namelen);
Index: cygwin/fhandler_socket.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/fhandler_socket.cc,v
retrieving revision 1.106
diff -u -r1.106 fhandler_socket.cc
--- cygwin/fhandler_socket.cc 30 Jun 2003 13:07:36 -0000 1.106
+++ cygwin/fhandler_socket.cc 3 Jul 2003 20:59:51 -0000
@@ -320,6 +320,7 @@
if (get_addr_family () == AF_LOCAL)
fhs->set_sun_path (get_sun_path ());
fhs->set_socket_type (get_socket_type ());
+ fhs->set_connect_state (get_connect_state ());
if (winsock2_active)
{
Index: cygwin/net.cc
===================================================================
RCS file: /cvs/src/src/winsup/cygwin/net.cc,v
retrieving revision 1.146
diff -u -r1.146 net.cc
--- cygwin/net.cc 19 Jun 2003 00:57:26 -0000 1.146
+++ cygwin/net.cc 3 Jul 2003 20:59:52 -0000
@@ -1997,7 +1997,10 @@
if (res_fd >= 0)
fh = fdsock (res_fd, "/dev/tcp", res);
if (fh)
- res = res_fd;
+ {
+ fh->set_connect_state (CONNECTED);
+ res = res_fd;
+ }
else
{
closesocket (res);
@@ -2011,8 +2014,11 @@
fh = NULL;
if (newfd >= 0)
fh = fdsock (newfd, "/dev/tcp", fd2s);
- if (fh)
- *fd2p = newfd;
+ if (fh)
+ {
+ *fd2p = newfd;
+ fh->set_connect_state (CONNECTED);
+ }
else
{
closesocket (res);
@@ -2081,7 +2087,10 @@
if (res_fd >= 0)
fh = fdsock (res_fd, "/dev/tcp", res);
if (fh)
- res = res_fd;
+ {
+ fh->set_connect_state (CONNECTED);
+ res = res_fd;
+ }
else
{
closesocket (res);
@@ -2096,7 +2105,10 @@
if (newfd >= 0)
fh = fdsock (newfd, "/dev/tcp", fd2s);
if (fh)
- *fd2p = newfd;
+ {
+ fh->set_connect_state (CONNECTED);
+ *fd2p = newfd;
+ }
else
{
closesocket (res);
@@ -2272,6 +2284,7 @@
fh->set_sun_path ("");
fh->set_addr_family (family);
fh->set_socket_type (type);
+ fh->set_connect_state (CONNECTED);
cygheap_fdnew sb1 (sb0, false);
@@ -2283,6 +2296,7 @@
fh->set_sun_path ("");
fh->set_addr_family (family);
fh->set_socket_type (type);
+ fh->set_connect_state (CONNECTED);
sb[0] = sb0;
sb[1] = sb1;
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