[MINOR] add the ability to force kernel socket buffer size.

Sometimes we need to be able to change the default kernel socket
buffer size (recv and send). Four new global settings have been
added for this :
   - tune.rcvbuf.client
   - tune.rcvbuf.server
   - tune.sndbuf.client
   - tune.sndbuf.server

Those can be used to reduce kernel memory footprint with large numbers
of concurrent connections, and to reduce risks of write timeouts with
very slow clients due to excessive kernel buffering.

diff --git a/doc/configuration.txt b/doc/configuration.txt
index 9d980748532c25426d851f827d9f36f666311e11..d626ade86b295bea52642166443129c365fc88ba 100644 (file)
--- a/doc/configuration.txt
+++ b/doc/configuration.txt
@@ -399,6 +399,10 @@ The following keywords are supported in the "global" section :
    - tune.maxaccept
    - tune.maxpollevents
    - tune.maxrewrite
+   - tune.rcvbuf.client
+   - tune.rcvbuf.server
+   - tune.sndbuf.client
+   - tune.sndbuf.server
 
  * Debugging
    - debug
@@ -639,6 +643,29 @@ tune.maxrewrite <number>
   larger than that. This means you don't have to worry about it when changing
   bufsize.
 
+tune.rcvbuf.client <number>
+tune.rcvbuf.server <number>
+  Forces the kernel socket receive buffer size on the client or the server side
+  to the specified value in bytes. This value applies to all TCP/HTTP frontends
+  and backends. It should normally never be set, and the default size (0) lets
+  the kernel autotune this value depending on the amount of available memory.
+  However it can sometimes help to set it to very low values (eg: 4096) in
+  order to save kernel memory by preventing it from buffering too large amounts
+  of received data. Lower values will significantly increase CPU usage though.
+
+tune.sndbuf.client <number>
+tune.sndbuf.server <number>
+  Forces the kernel socket send buffer size on the client or the server side to
+  the specified value in bytes. This value applies to all TCP/HTTP frontends
+  and backends. It should normally never be set, and the default size (0) lets
+  the kernel autotune this value depending on the amount of available memory.
+  However it can sometimes help to set it to very low values (eg: 4096) in
+  order to save kernel memory by preventing it from buffering too large amounts
+  of received data. Lower values will significantly increase CPU usage though.
+  Another use case is to prevent write timeouts with extremely slow clients due
+  to the kernel waiting for a large part of the buffer to be read before
+  notifying haproxy again.
+
 
 3.3. Debugging
 --------------

diff --git a/include/types/global.h b/include/types/global.h
index 2a7bc4609b9d15267d4d5cb24c3656f16da56d65..463bd3876d4576874cd7498a7dde491cb036dc6c 100644 (file)
--- a/include/types/global.h
+++ b/include/types/global.h
@@ -87,6 +87,10 @@ struct global {
                int recv_enough;   /* how many input bytes at once are "enough" */
                int bufsize;       /* buffer size in bytes, defaults to BUFSIZE */
                int maxrewrite;    /* buffer max rewrite size in bytes, defaults to MAXREWRITE */
+               int client_sndbuf; /* set client sndbuf to this value if not null */
+               int client_rcvbuf; /* set client rcvbuf to this value if not null */
+               int server_sndbuf; /* set server sndbuf to this value if not null */
+               int server_rcvbuf; /* set server rcvbuf to this value if not null */
        } tune;
        struct listener stats_sock; /* unix socket listener for statistics */
        struct proxy *stats_fe;     /* the frontend holding the stats settings */

diff --git a/src/cfgparse.c b/src/cfgparse.c
index 39a79f2f7b49fd556e777557b4e57597d6de8472..9aae768ab255bde68e3113e0983928c417818661 100644 (file)
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -475,6 +475,58 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
                if (global.tune.maxrewrite >= global.tune.bufsize / 2)
                        global.tune.maxrewrite = global.tune.bufsize / 2;
        }
+       else if (!strcmp(args[0], "tune.rcvbuf.client")) {
+               if (global.tune.client_rcvbuf != 0) {
+                       Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT;
+                       goto out;
+               }
+               if (*(args[1]) == 0) {
+                       Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT | ERR_FATAL;
+                       goto out;
+               }
+               global.tune.client_rcvbuf = atol(args[1]);
+       }
+       else if (!strcmp(args[0], "tune.rcvbuf.server")) {
+               if (global.tune.server_rcvbuf != 0) {
+                       Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT;
+                       goto out;
+               }
+               if (*(args[1]) == 0) {
+                       Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT | ERR_FATAL;
+                       goto out;
+               }
+               global.tune.server_rcvbuf = atol(args[1]);
+       }
+       else if (!strcmp(args[0], "tune.sndbuf.client")) {
+               if (global.tune.client_sndbuf != 0) {
+                       Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT;
+                       goto out;
+               }
+               if (*(args[1]) == 0) {
+                       Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT | ERR_FATAL;
+                       goto out;
+               }
+               global.tune.client_sndbuf = atol(args[1]);
+       }
+       else if (!strcmp(args[0], "tune.sndbuf.server")) {
+               if (global.tune.server_sndbuf != 0) {
+                       Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT;
+                       goto out;
+               }
+               if (*(args[1]) == 0) {
+                       Alert("parsing [%s:%d] : '%s' expects an integer argument.\n", file, linenum, args[0]);
+                       err_code |= ERR_ALERT | ERR_FATAL;
+                       goto out;
+               }
+               global.tune.server_sndbuf = atol(args[1]);
+       }
        else if (!strcmp(args[0], "uid")) {
                if (global.uid != 0) {
                        Alert("parsing [%s:%d] : user/uid already specified. Continuing.\n", file, linenum);

diff --git a/src/client.c b/src/client.c
index 458bb1c2c937cb90d3276a09b2dcc7b5f650c476..f27424534339f0c8e4e9831a60f67512ac45e519 100644 (file)
--- a/src/client.c
+++ b/src/client.c
@@ -172,6 +172,12 @@ int event_accept(int fd) {
                if (p->options & PR_O_TCP_NOLING)
                        setsockopt(cfd, SOL_SOCKET, SO_LINGER, (struct linger *) &nolinger, sizeof(struct linger));
 
+               if (global.tune.client_sndbuf)
+                       setsockopt(cfd, SOL_SOCKET, SO_SNDBUF, &global.tune.client_sndbuf, sizeof(global.tune.client_sndbuf));
+
+               if (global.tune.client_rcvbuf)
+                       setsockopt(cfd, SOL_SOCKET, SO_RCVBUF, &global.tune.client_rcvbuf, sizeof(global.tune.client_rcvbuf));
+
                t->process = l->handler;
                t->context = s;
                t->nice = l->nice;

diff --git a/src/proto_tcp.c b/src/proto_tcp.c
index b2efa0b78298d489ff80c89ab2880f1cea66c439..23f3ac93c23e23a45729da0b843cd98229689b67 100644 (file)
--- a/src/proto_tcp.c
+++ b/src/proto_tcp.c
@@ -378,6 +378,12 @@ int tcpv4_connect_server(struct stream_interface *si,
                 setsockopt(fd, IPPROTO_TCP, TCP_QUICKACK, (char *) &zero, sizeof(zero));
 #endif
 
+       if (global.tune.server_sndbuf)
+                setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &global.tune.server_sndbuf, sizeof(global.tune.server_sndbuf));
+
+       if (global.tune.server_rcvbuf)
+                setsockopt(fd, SOL_SOCKET, SO_RCVBUF, &global.tune.server_rcvbuf, sizeof(global.tune.server_rcvbuf));
+
        if ((connect(fd, (struct sockaddr *)srv_addr, sizeof(struct sockaddr_in)) == -1) &&
            (errno != EINPROGRESS) && (errno != EALREADY) && (errno != EISCONN)) {