upstream/haproxy
1
0
Fork 0
mirror of https://github.com/haproxy/haproxy.git synced 2026-06-08 16:23:24 -04:00
Code Issues Projects Releases Packages Wiki Activity Actions 4

MINOR: mux-h2: permit to fix a minimum value for the advertised streams limit

Browse source 
When using rq-load on tune.h2.fe.max-concurrent-streams, it's easy to
reach a situation where only one stream is allowed. There's nothing
wrong with this but it turns out that slightly higher values do not
necessarily cause significantly higher loads and will improve the user
experience. For this reason the keyword now also supports "min" to
specify a value. Experimentation shows that values from 5 to 15 remain
very effective at protecting the run queue while allowing a great level
of parallelism that keeps a site fluid.
This commit is contained in:
Willy Tarreau 2026-03-19 16:00:05 +01:00
parent c238965b27
commit 932d77e287
2 changed files with 41 additions and 15 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

11
doc/configuration.txt
View file

@ -4447,6 +4447,17 @@ tune.h2.fe.max-concurrent-streams <number> [args...]
value, which generally provides good results without having to tweak
the configuration any further.
- min <number>:
This sets the minimum advertised concurrency level when rq-load is used,
even if this results in a higher load than the configured target. This
allows to maintain a good level of interactivity on a site under very
heavy load. The minimum and default value is 1, but values between 5
and 15 can improve user experience.
Example:
tune.h2.fe.max-concurrent-streams 100 rq-load auto min 15
tune.h2.fe.max-total-streams <number>
Sets the HTTP/2 maximum number of total streams processed per incoming
connection. Once this limit is reached, HAProxy will send a graceful GOAWAY

45
src/mux_h2.c
View file

@ -492,6 +492,7 @@ static uint h2_fe_rxbuf = 0; /* frontend's default tot
static unsigned int h2_settings_max_concurrent_streams = 100; /* default value */
static unsigned int h2_be_settings_max_concurrent_streams = 0; /* backend value */
static unsigned int h2_fe_settings_max_concurrent_streams = 0; /* frontend value */
static unsigned int h2_fe_min_concurrent_streams = 1; /* minimum concurrent streams when using rq-load */
static unsigned int h2_fe_max_rq_load = ~0; /* max rq for FE dynamic MCS sizing. 0=def rq */
static int h2_settings_max_frame_size = 0; /* unset */
static int h2_settings_log_errors = H2_ERR_LOG_ERR_STRM;
@ -771,7 +772,8 @@ static inline int h2c_max_concurrent_streams(const struct h2c *h2c)
*/
if (load > limit)
ret = (uint64_t)ret * limit / load * limit / load;
ret = ret ? ret : 1;
if (ret < h2_fe_min_concurrent_streams)
ret = h2_fe_min_concurrent_streams;
}
return ret;
}
@ -8724,6 +8726,7 @@ static int h2_parse_max_concurrent_streams(char **args, int section_type, struct
char **err)
{
uint *vptr;
int arg;
/* backend/frontend/default */
vptr = (args[0][8] == 'b') ? &h2_be_settings_max_concurrent_streams :
@ -8731,8 +8734,7 @@ static int h2_parse_max_concurrent_streams(char **args, int section_type, struct
&h2_settings_max_concurrent_streams;
if ((args[0][8] != 'f' && too_many_args(1, args, err, NULL)) ||
too_many_args(3, args, err, NULL))
if (args[0][8] != 'f' && too_many_args(1, args, err, NULL))
return -1;
*vptr = atoi(args[1]);
@ -8745,21 +8747,34 @@ static int h2_parse_max_concurrent_streams(char **args, int section_type, struct
goto leave;
/* tune.h2.fe. here */
if (strcmp(args[2], "rq-load") == 0) {
if (strcmp(args[3], "ignore") == 0)
h2_fe_max_rq_load = ~0;
else if (strcmp(args[3], "auto") == 0)
h2_fe_max_rq_load = 0;
else if (!*args[3] || (h2_fe_max_rq_load = atoi(args[3])) <= 0) {
memprintf(err, "'%s' expects a strictly positive run-queue length, or 'auto' or 'ignore'.", args[0]);
for (arg = 2; *args[arg]; arg += 2) {
if (strcmp(args[arg], "rq-load") == 0) {
if (strcmp(args[arg + 1], "ignore") == 0)
h2_fe_max_rq_load = ~0;
else if (strcmp(args[arg + 1], "auto") == 0)
h2_fe_max_rq_load = 0;
else if (!*args[arg + 1] || (h2_fe_max_rq_load = atoi(args[arg + 1])) <= 0) {
memprintf(err, "'%s' expects a strictly positive run-queue length, or 'auto' or 'ignore'.", args[0]);
return -1;
}
}
else if (strcmp(args[arg], "min") == 0) {
if (!*args[arg + 1] || (h2_fe_min_concurrent_streams = atoi(args[arg + 1])) <= 0) {
memprintf(err, "'%s' expects a strictly positive minimum number of streams'.", args[0]);
return -1;
}
if (h2_fe_min_concurrent_streams > h2_fe_settings_max_concurrent_streams) {
memprintf(err, "'%s' minimum number of streams (%u) cannot be higher than the maximum (%u)'.",
args[0], h2_fe_min_concurrent_streams, h2_fe_settings_max_concurrent_streams);
return -1;
}
}
else if (*args[arg]) {
memprintf(err, "'%s' only supports 'rq-load' or 'min' after the numeric value, but found '%s'.", args[0], args[arg]);
return -1;
}
}
else if (*args[2]) {
memprintf(err, "'%s' only supports 'rq-load' after the numeric value, but found '%s'.", args[0], args[2]);
return -1;
}
leave:
return 0;
}