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[MEDIUM] remove TCP_CORK and make use of MSG_MORE instead

Browse source 
send() supports the MSG_MORE flag on Linux, which does the same
as TCP_CORK except that we don't have to remove TCP_NODELAY before
and we don't need any syscall to set/remove it. This can save up
to 4 syscalls around a send() (two for setting it, two for removing
it), and it's much cleaner since it is not persistent. So make use
of it instead.
This commit is contained in:
Willy Tarreau 2009-08-19 11:14:11 +02:00
parent d6d06909da
commit 6db06d3870
3 changed files with 25 additions and 36 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

5
include/common/compat.h
View file

@ -66,6 +66,11 @@
#define MSG_DONTWAIT 0
#endif
/* Only Linux defines MSG_MORE */
#ifndef MSG_MORE
#define MSG_MORE 0
#endif
#if defined(TPROXY) && defined(NETFILTER)
#include <linux/types.h>
#include <linux/netfilter_ipv6.h>

3
include/types/fd.h
View file

@ -63,8 +63,7 @@ enum {
*/
#define FD_FL_TCP 0x0001 /* socket is TCP */
#define FD_FL_TCP_NODELAY 0x0002
#define FD_FL_TCP_CORK 0x0004
#define FD_FL_TCP_NOLING 0x0008 /* lingering disabled */
#define FD_FL_TCP_NOLING 0x0004 /* lingering disabled */
/* info about one given fd */
struct fdtab {

53
src/stream_sock.c
View file

@ -585,28 +585,28 @@ static int stream_sock_write_loop(struct stream_interface *si, struct buffer *b)
if (max > b->send_max)
max = b->send_max;
#if defined(TCP_CORK) && defined(SOL_TCP)
/*
* Check if we want to cork output before sending. This typically occurs
* when there are data left in the buffer, or when we reached the end of
* buffer but we know we will close, so we try to merge the ongoing FIN
* with the last data segment.
/* check if we want to inform the kernel that we're interested in
* sending more data after this call. We want this if :
* - we're about to close after this last send and want to merge
* the ongoing FIN with the last segment.
* - we know we can't send everything at once and must get back
* here because of unaligned data
* The test is arranged so that the most common case does only 2
* tests.
*/
if ((fdtab[si->fd].flags & (FD_FL_TCP|FD_FL_TCP_NOLING|FD_FL_TCP_CORK)) == FD_FL_TCP) {
if (unlikely((b->send_max == b->l &&
(b->flags & (BF_SHUTW|BF_SHUTW_NOW|BF_HIJACK|BF_WRITE_ENA|BF_SHUTR)) ==
(BF_WRITE_ENA|BF_SHUTR)))) {
/* we have to unconditionally reset TCP_NODELAY for CORK */
setsockopt(si->fd, IPPROTO_TCP, TCP_NODELAY, (char *) &zero, sizeof(zero));
setsockopt(si->fd, SOL_TCP, TCP_CORK, (char *) &one, sizeof(one));
fdtab[si->fd].flags = (fdtab[si->fd].flags & ~FD_FL_TCP_NODELAY) | FD_FL_TCP_CORK;
}
}
#endif
if (MSG_NOSIGNAL) {
ret = send(si->fd, b->w, max, MSG_DONTWAIT | MSG_NOSIGNAL);
unsigned int send_flag = MSG_DONTWAIT | MSG_NOSIGNAL;
if (MSG_MORE &&
(((b->flags & (BF_SHUTW|BF_SHUTW_NOW|BF_HIJACK|BF_WRITE_ENA|BF_SHUTR)) == (BF_WRITE_ENA|BF_SHUTR) &&
(max == b->l)) ||
(max != b->l && max != b->send_max))
&& (fdtab[si->fd].flags & FD_FL_TCP)) {
send_flag |= MSG_MORE;
}
ret = send(si->fd, b->w, max, send_flag);
} else {
int skerr;
socklen_t lskerr = sizeof(skerr);
@ -662,21 +662,6 @@ static int stream_sock_write_loop(struct stream_interface *si, struct buffer *b)
}
} /* while (1) */
/* check if we need to uncork the output, for instance when the
* output buffer is empty but not shutr().
*/
if (unlikely((fdtab[si->fd].flags & (FD_FL_TCP|FD_FL_TCP_NODELAY)) == FD_FL_TCP && (b->flags & BF_EMPTY))) {
if ((b->flags & (BF_SHUTW|BF_SHUTW_NOW|BF_HIJACK|BF_WRITE_ENA|BF_SHUTR)) != (BF_WRITE_ENA|BF_SHUTR)) {
#if defined(TCP_CORK) && defined(SOL_TCP)
if (fdtab[si->fd].flags & FD_FL_TCP_CORK)
setsockopt(si->fd, SOL_TCP, TCP_CORK, (char *) &zero, sizeof(zero));
#endif
setsockopt(si->fd, IPPROTO_TCP, TCP_NODELAY, (char *) &one, sizeof(one));
fdtab[si->fd].flags = (fdtab[si->fd].flags & ~FD_FL_TCP_CORK) | FD_FL_TCP_NODELAY;
}
}
return retval;
}