change the writes to a writev for tcp, performance improves drasticly

SCCS-vsn: lib/libc/net/res_send.c 6.12

diff --git a/usr/src/lib/libc/net/res_send.c b/usr/src/lib/libc/net/res_send.c
index 6ecde76..02fbbda 100644 (file)
--- a/usr/src/lib/libc/net/res_send.c
+++ b/usr/src/lib/libc/net/res_send.c
@@ -6,7 +6,7 @@
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)
  */
 
 #if defined(LIBC_SCCS) && !defined(lint)

-static char sccsid[] = "@(#)res_send.c 6.11 (Berkeley) %G%";
+static char sccsid[] = "@(#)res_send.c 6.12 (Berkeley) %G%";

 #endif LIBC_SCCS and not lint
 
 /*
 #endif LIBC_SCCS and not lint
 
 /*


@@ -16,6 +16,7 @@ static char sccsid[] = "@(#)res_send.c        6.11 (Berkeley) %G%";
 #include <sys/param.h>
 #include <sys/time.h>
 #include <sys/socket.h>
 #include <sys/param.h>
 #include <sys/time.h>
 #include <sys/socket.h>

+#include <sys/uio.h>

 #include <netinet/in.h>
 #include <stdio.h>
 #include <errno.h>
 #include <netinet/in.h>
 #include <stdio.h>
 #include <errno.h>


@@ -43,6 +44,7 @@ res_send(buf, buflen, answer, anslen)
        struct timeval timeout;
        HEADER *hp = (HEADER *) buf;
        HEADER *anhp = (HEADER *) answer;
        struct timeval timeout;
        HEADER *hp = (HEADER *) buf;
        HEADER *anhp = (HEADER *) answer;

+       struct iovec iov[2];

 
 #ifdef DEBUG
        if (_res.options & RES_DEBUG) {
 
 #ifdef DEBUG
        if (_res.options & RES_DEBUG) {


@@ -94,8 +96,11 @@ res_send(buf, buflen, answer, anslen)
                         * Send length & message
                         */
                        len = htons((u_short)buflen);
                         * Send length & message
                         */
                        len = htons((u_short)buflen);

-                       if (write(s, (char *)&len, sizeof(len)) != sizeof(len)||
-                           write(s, buf, buflen) != buflen) {
+                       iov[0].iov_base = (caddr_t)&len;
+                       iov[0].iov_len = sizeof(len);
+                       iov[1].iov_base = buf;
+                       iov[1].iov_len = buflen;
+                       if (writev(s, iov, 2) != sizeof(len) + buflen) {

 #ifdef DEBUG
                                if (_res.options & RES_DEBUG)
                                        perror("write failed");
 #ifdef DEBUG
                                if (_res.options & RES_DEBUG)
                                        perror("write failed");


@@ -109,7 +114,7 @@ res_send(buf, buflen, answer, anslen)
                         */
                        cp = answer;
                        len = sizeof(short);
                         */
                        cp = answer;
                        len = sizeof(short);

-                       while (len > 0 &&
+                       while (len != 0 &&

                            (n = read(s, (char *)cp, (int)len)) > 0) {
                                cp += n;
                                len -= n;
                            (n = read(s, (char *)cp, (int)len)) > 0) {
                                cp += n;
                                len -= n;


@@ -125,7 +130,7 @@ res_send(buf, buflen, answer, anslen)
                        }
                        cp = answer;
                        resplen = len = ntohs(*(u_short *)cp);
                        }
                        cp = answer;
                        resplen = len = ntohs(*(u_short *)cp);

-                       while (len > 0 &&
+                       while (len != 0 &&

                           (n = read(s, (char *)cp, (int)len)) > 0) {
                                cp += n;
                                len -= n;
                           (n = read(s, (char *)cp, (int)len)) > 0) {
                                cp += n;
                                len -= n;


@@ -175,7 +180,8 @@ res_send(buf, buflen, answer, anslen)
                        timeout.tv_usec = 0;
 wait:
                        dsmask = 1 << s;
                        timeout.tv_usec = 0;
 wait:
                        dsmask = 1 << s;

-                       n = select(s+1, &dsmask, 0, 0, &timeout);
+                       n = select(s+1, &dsmask, (fd_set *)NULL,
+                               (fd_set *)NULL, &timeout);

                        if (n < 0) {
 #ifdef DEBUG
                                if (_res.options & RES_DEBUG)
                        if (n < 0) {
 #ifdef DEBUG
                                if (_res.options & RES_DEBUG)