On Wed, Dec 04, 2002 at 07:12:04AM -0500, Jeff Trawick wrote:
> Colm MacC�rthaigh <[EMAIL PROTECTED]> writes:
>
> > O.k., now that is interesting, another thing I've noticed is that when
> > the encoding is chunked, I can't replicate the problem. Presumably the
> > problem is related to how much data is trying to be sent down the
> > socket at once.
>
> Well, note that Apache uses different socket APIs for dynamic content
> vs. static content, and chunking is only used for dynamic content.
> That should be related to the breakage.
>
> Also, the other poster mentioned that SSL works over IPv6 but non-SSL
> doesn't on one box. That also corresponds to the same difference in
> socket API usage.
>
> We can't use sendfile for any dynamic content. We can't use sendfile
> for encrypted static or encrypted dynamic content. So it really seems
> that sendfile is key to the issue.
Looks very much like that is the case.
> But I'm confused because you already disabled sendfile usage and that
> didn't bring some amount of happiness. Also, the path where we use
> sendfile is the path where we use TCP_CORK so how can there be a
> problem if we don't use sendfile()?
>
> double-checking where TCP_CORK is used:
>
> 1) APR_TCP_NOPUSH_FLAG is TCP_CORK on Linux
> 2) APR_TCP_NOPUSH socket option controls APR_TCP_NOPUSH_FLAG
> 3) apr_sendfile() for Linux is the only code that dorks with
> APR_TCP_NOPUSH (and thus TCP_CORK)
Here's what I see , when I use --disable-sendfile, this is a successful
request:
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "GET / HTTP/1.1\r\n", 8000) = 16
gettimeofday({1039003895, 580353}, NULL) = 0
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "Host: www.heanet.ie\r\n", 8000) = 21
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "\r\n", 8000) = 2
stat64("/usr/local/apache/htdocs/", {st_mode=S_IFDIR|S_ISGID|0755,
st_size=4096, ...}) = 0
brk(0x814c000) = 0x814c000
stat64("/usr/local/apache/htdocs/index.html", {st_mode=S_IFREG|0644,
st_size=256, ...}) = 0
open("/usr/local/apache/htdocs/index.html", O_RDONLY) = 9
brk(0x814f000) = 0x814f000
read(8, 0x8146a30, 8000) = -1 EAGAIN (Resource
temporarily unavailable)
setsockopt(8, SOL_TCP, TCP_NODELAY, [0], 4) = 0
setsockopt(8, SOL_TCP, TCP_CORK, [1], 4) = 0
writev(8, [{"HTTP/1.1 200 OK\r\nDate: Wed, 04 D"..., 248}], 1) = 248
sendfile(8, 9, [0], 256) = 256
setsockopt(8, SOL_TCP, TCP_CORK, [0], 4) = 0
setsockopt(8, SOL_TCP, TCP_NODELAY, [1], 4) = 0
write(4, "2001:770:18:1:201:2ff:fef0:f281 "..., 90) = 90
poll(^C
<unfinished ...>
and this is an unsuccessful one:
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "GET / HTTP/1.1\r\n", 8000) = 16
gettimeofday({1039003973, 629255}, NULL) = 0
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "Host: www.heanet.ie\r\n", 8000) = 21
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 300000) = 1
read(8, "\r\n", 8000) = 2
stat64("/usr/local/apache/htdocs/", {st_mode=S_IFDIR|S_ISGID|0755,
st_size=4096, ...}) = 0
brk(0x814c000) = 0x814c000
stat64("/usr/local/apache/htdocs/index.html", {st_mode=S_IFREG|0644,
st_size=256, ...}) = 0
open("/usr/local/apache/htdocs/index.html", O_RDONLY) = 9
brk(0x814f000) = 0x814f000
read(8, 0x8146a30, 8000) = -1 EAGAIN (Resource
temporarily unavailable)
setsockopt(8, SOL_TCP, TCP_NODELAY, [0], 4) = 0
setsockopt(8, SOL_TCP, TCP_CORK, [1], 4) = 0
writev(8, [{"HTTP/1.1 200 OK\r\nDate: Wed, 04 D"..., 248}], 1) = 248
sendfile(8, 9, [0], 256) = 256
setsockopt(8, SOL_TCP, TCP_CORK, [0], 4) = 0
setsockopt(8, SOL_TCP, TCP_NODELAY, [1], 4) = 0
write(4, "2001:770:18:1:201:2ff:fef0:f281 "..., 90) = 90
poll([{fd=8, events=POLLIN, revents=POLLIN}], 1, 15000) = 1
read(8, "", 8000) = 0
gettimeofday({1039003977, 946871}, NULL) = 0
shutdown(8, 1 /* send */) = 0
poll([{fd=8, events=POLLIN, revents=POLLIN|POLLHUP}], 1, 2000) = 1
read(8, "", 512) = 0
close(8) = 0
read(5, 0xbffffb77, 1) = -1 EAGAIN (Resource
temporarily unavailable)
close(9) = 0
accept(3, <unfinished ...>
> So I still don't understand why disabling sendfile usage didn't avoid
> the problem, unless it isn't specific to TCP_CORK after all.
Looks like the --disable-sendfile doesnt work, it's still using
sendfile. Reading the configure.in tells me you meant
--without-sendfile ;-) Which does do as would be expected, the
problem goes away.
I've written a patch, to confirm that it is really
TCP_CORK, applied it, and tested it, and when I use the new
--disable-ipv6-tcp-cork option, everything is nice and happy :-)
Wether I use sendfile or not.
My tests (and patch) were based on apr and apr-util from CVS ,
with the 2.0.43 codebase, because CVS seems broken right now.
Index: configure.in
===================================================================
RCS file: /home/cvspublic/apr/configure.in,v
retrieving revision 1.506
diff -u -r1.506 configure.in
--- configure.in 2 Dec 2002 16:07:09 -0000 1.506
+++ configure.in 4 Dec 2002 10:29:45 -0000
@@ -1770,6 +1770,16 @@
echo "${nl}Checking for IPv6 Networking support..."
dnl Start of checking for IPv6 support...
+ipv6_tcp_cork=1
+AC_ARG_ENABLE(ipv6-tcp-cork,
+ [ --disable-ipv6-tcp-cork Disable TCP_CORK with IPv6.],
+ [ if test "$enableval" = "no"; then
+ use_ipv6_tcp_cork=0
+ fi ],
+ [ use_ipv6_tcp_cork=1 ] )
+
+AC_SUBST(use_ipv6_tcp_cork)
+
AC_ARG_ENABLE(ipv6,
[ --disable-ipv6 Disable IPv6 support in APR.],
[ if test "$enableval" = "no"; then
Index: include/apr.h.in
===================================================================
RCS file: /home/cvspublic/apr/include/apr.h.in,v
retrieving revision 1.117
diff -u -r1.117 apr.h.in
--- include/apr.h.in 22 Oct 2002 12:37:40 -0000 1.117
+++ include/apr.h.in 4 Dec 2002 10:29:46 -0000
@@ -171,6 +171,11 @@
*/
#define APR_TCP_NOPUSH_FLAG @apr_tcp_nopush_flag@
+/* Should we use "corked" TCP with IPv6 ? (this seems to be broken on
+ * linux
+ */
+#define APR_USE_IPV6_TCP_CORK @use_ipv6_tcp_cork@
+
/* Is the TCP_NODELAY socket option inherited from listening sockets?
*/
#define APR_TCP_NODELAY_INHERITED @tcp_nodelay_inherited@
Index: network_io/unix/sockopt.c
===================================================================
RCS file: /home/cvspublic/apr/network_io/unix/sockopt.c,v
retrieving revision 1.63
diff -u -r1.63 sockopt.c
--- network_io/unix/sockopt.c 20 Nov 2002 03:50:21 -0000 1.63
+++ network_io/unix/sockopt.c 4 Dec 2002 10:29:46 -0000
@@ -259,9 +259,15 @@
return APR_ENOTIMPL;
#endif
}
- if (opt & APR_TCP_NOPUSH) {
+ if (opt & APR_TCP_NOPUSH
+#ifndef APR_USE_IPV6_TCP_CORK
+ sd;fl sd;klfjss ds;lkfjds
+ && sock->remoteaddr->sa.sin.sin_family != APR_INET6
+#endif
+ ) {
+
#if APR_TCP_NOPUSH_FLAG
- if (apr_is_option_set(sock->netmask, APR_TCP_NOPUSH) != on) {
+ if (apr_is_option_set(sock->netmask, APR_TCP_NOPUSH) != on) {
int optlevel = IPPROTO_TCP;
int optname = TCP_NODELAY;
--
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