MINOR: compression: maximum compression rate limit

This patch adds input and output rate calcutation on the HTTP compresion
feature.

Compression can be limited with a maximum rate value in kilobytes per
second. The rate is set with the global 'maxcomprate' option. You can
change this value dynamicaly with 'set rate-limit http-compression
global' on the UNIX socket.

doc/configuration.txt

@@ -455,6 +455,7 @@ The following keywords are supported in the "global" section :
  * Performance tuning
    - maxconn
    - maxconnrate
+   - maxcomprate
    - maxpipes
    - maxsslconn
    - noepoll
@@ -672,6 +673,15 @@ maxconnrate <number>
   value close to its expected share. Also, lowering tune.maxaccept can improve
   fairness.
 
+maxcomprate <number>
+  Sets the maximum per-process input compression rate to <number> kilobytes
+  pers second.  For each session, if the maximum is reached, the compression
+  level will be decreased during the session. If the maximum is reached at the
+  beginning of a session, the session will not compress at all. If the maximum
+  is not reached, the compression level will be increased up to
+  tune.comp.maxlevel.  A value of zero means there is no limit, this is the
+  default value.
+
 maxpipes <number>
   Sets the maximum per-process number of pipes to <number>. Currently, pipes
   are only used by kernel-based tcp splicing. Since a pipe contains two file
@@ -11110,6 +11120,11 @@ set rate-limit connections global <value>
   applies to all frontends and the change has an immediate effect. The value
   is passed in number of connections per second.
 
+set rate-limit http-compression global <value>
+  Change the maximum input compression rate, which is set by the global
+  'maxcomprate' setting. A value of zero disables the limitation. The value is
+  passed in number of kilobytes per second.
+
 set table <table> key <key> data.<data_type> <value>
   Create or update a stick-table entry in the table. If the key is not present,
   an entry is inserted. See stick-table in section 4.2 to find all possible

include/types/global.h

@@ -80,7 +80,10 @@ struct global {
 	char *connect_default_ciphers;
 #endif
 	struct freq_ctr conn_per_sec;
+	struct freq_ctr comp_bps_in;	/* bytes per second, before http compression */
+	struct freq_ctr comp_bps_out;	/* bytes per second, after http compression */
 	int cps_lim, cps_max;
+	int comp_rate_lim;           /* HTTP compression rate limit */
 	int maxpipes;		/* max # of pipes */
 	int maxsock;		/* max # of sockets */
 	int rlimit_nofile;	/* default ulimit-n value : 0=unset */

src/cfgparse.c

@@ -844,6 +844,14 @@ int cfg_parse_global(const char *file, int linenum, char **args, int kwm)
 		}
 		global.cps_lim = atol(args[1]);
 	}
+	else if (!strcmp(args[0], "maxcomprate")) {
+		if (*(args[1]) == 0) {
+			Alert("parsing [%s:%d] : '%s' expects an integer argument in kb/s.\n", file, linenum, args[0]);
+			err_code |= ERR_ALERT | ERR_FATAL;
+			goto out;
+		}
+		global.comp_rate_lim = atoi(args[1]) * 1024;
+	}
 	else if (!strcmp(args[0], "maxpipes")) {
 		if (global.maxpipes != 0) {
 			Alert("parsing [%s:%d] : '%s' already specified. Continuing.\n", file, linenum, args[0]);

src/compression.c

@@ -31,6 +31,7 @@
 #include <types/compression.h>
 
 #include <proto/compression.h>
+#include <proto/freq_ctr.h>
 #include <proto/proto_http.h>
 
 
@@ -261,6 +262,10 @@ int http_compression_buffer_end(struct session *s, struct buffer **in, struct bu
 
 	to_forward = ob->i;
 
+	/* update input rate */
+	if (s->comp_ctx.cur_lvl > 0)
+		update_freq_ctr(&global.comp_bps_in, ib->o - ob->o);
+
 	/* copy the remaining data in the tmp buffer. */
 	if (ib->i > 0) {
 		left = ib->i - bi_contig_data(ib);
@@ -276,6 +281,9 @@ int http_compression_buffer_end(struct session *s, struct buffer **in, struct bu
 	*in = ob;
 	*out = ib;
 
+	if (s->comp_ctx.cur_lvl > 0)
+		update_freq_ctr(&global.comp_bps_out, to_forward);
+
 	/* forward the new chunk without remaining data */
 	b_adv(ob, to_forward);
 
@@ -490,6 +498,23 @@ int deflate_flush(struct comp_ctx *comp_ctx, struct buffer *out, int flag)
 	out_len = (out->size - buffer_len(out)) - strm->avail_out;
 	out->i += out_len;
 
+	/* compression rate limit */
+	if (global.comp_rate_lim > 0) {
+
+		if (read_freq_ctr(&global.comp_bps_out) > global.comp_rate_lim) {
+			/* decrease level */
+			if (comp_ctx->cur_lvl > 0) {
+				comp_ctx->cur_lvl--;
+				deflateParams(&comp_ctx->strm, comp_ctx->cur_lvl, Z_DEFAULT_STRATEGY);
+			}
+
+		} else if (comp_ctx->cur_lvl < global.comp_rate_lim) {
+			/* increase level */
+			comp_ctx->cur_lvl++ ;
+			deflateParams(&comp_ctx->strm, comp_ctx->cur_lvl, Z_DEFAULT_STRATEGY);
+		}
+	}
+
 	return out_len;
 }
 

src/dumpstats.c

@@ -1246,8 +1246,21 @@ static int stats_sock_parse_request(struct stream_interface *si, char *line)
 					return 1;
 				}
 			}
+			else if (strcmp(args[2], "http-compression") == 0) {
+				if (strcmp(args[3], "global") == 0) {
+					int v;
+
+					v = atoi(args[4]);
+					global.comp_rate_lim = v * 1024; /* Kilo to bytes. */
+				}
+				else {
+					si->applet.ctx.cli.msg = "'set rate-limit http-compression' only supports 'global'.\n";
+					si->applet.st0 = STAT_CLI_PRINT;
+					return 1;
+				}
+			}
 			else {
-				si->applet.ctx.cli.msg = "'set rate-limit' only supports 'connections'.\n";
+				si->applet.ctx.cli.msg = "'set rate-limit' supports 'connections' and 'http-compression'.\n";
 				si->applet.st0 = STAT_CLI_PRINT;
 				return 1;
 			}
@@ -1708,6 +1721,8 @@ static int stats_dump_raw_to_buffer(struct stream_interface *si)
 				     "ConnRate: %d\n"
 				     "ConnRateLimit: %d\n"
 				     "MaxConnRate: %d\n"
+				     "CompressBpsIn: %u\n"
+				     "CompressBpsOut: %u\n"
 				     "Tasks: %d\n"
 				     "Run_queue: %d\n"
 				     "Idle_pct: %d\n"
@@ -1724,6 +1739,7 @@ static int stats_dump_raw_to_buffer(struct stream_interface *si)
 				     global.maxsock, global.maxconn, global.hardmaxconn, global.maxpipes,
 				     actconn, pipes_used, pipes_free,
 				     read_freq_ctr(&global.conn_per_sec), global.cps_lim, global.cps_max,
+				     read_freq_ctr(&global.comp_bps_in), read_freq_ctr(&global.comp_bps_out),
 				     nb_tasks_cur, run_queue_cur, idle_pct,
 				     global.node, global.desc?global.desc:""
 				     );

src/haproxy.c

@@ -113,6 +113,7 @@ struct global global = {
 	.req_count = 0,
 	.logsrvs = LIST_HEAD_INIT(global.logsrvs),
 	.maxzlibmem = 0,
+	.comp_rate_lim = 0,
 	.unix_bind = {
 		 .ux = {
 			 .uid = -1,

src/proto_http.c

@@ -2087,6 +2087,11 @@ int select_compression_response_header(struct session *s, struct buffer *res)
 
 	ctx.idx = 0;
 
+	/* limit compression rate */
+	if (global.comp_rate_lim > 0)
+		if (read_freq_ctr(&global.comp_bps_in) > global.comp_rate_lim)
+			goto fail;
+
 	/* initialize compression */
 	if (s->comp_algo->init(&s->comp_ctx, global.tune.comp_maxlevel) < 0)
 		goto fail;