net_sched: htb: do not setup default rate estimators
With a thousand htb classes, est_timer() spends ~5 million cpu cycles
and throws out cpu cache, because each htb class has a default
rate estimator (est 4sec 16sec).
Most users do not use default rate estimators, so switch htb
to not setup ones.
Add a module parameter (htb_rate_est) so that users relying
on this default rate estimator can revert the behavior.
echo 1 >/sys/module/sch_htb/parameters/htb_rate_est
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c
index 162fb80..1a3655a 100644
--- a/net/sched/sch_htb.c
+++ b/net/sched/sch_htb.c
@@ -65,6 +65,10 @@
module_param (htb_hysteresis, int, 0640);
MODULE_PARM_DESC(htb_hysteresis, "Hysteresis mode, less CPU load, less accurate");
+static int htb_rate_est = 0; /* htb classes have a default rate estimator */
+module_param(htb_rate_est, int, 0640);
+MODULE_PARM_DESC(htb_rate_est, "setup a default rate estimator (4sec 16sec) for htb classes");
+
/* used internaly to keep status of single class */
enum htb_cmode {
HTB_CANT_SEND, /* class can't send and can't borrow */
@@ -1366,12 +1370,14 @@
if (!cl)
goto failure;
- err = gen_new_estimator(&cl->bstats, &cl->rate_est,
- qdisc_root_sleeping_lock(sch),
- tca[TCA_RATE] ? : &est.nla);
- if (err) {
- kfree(cl);
- goto failure;
+ if (htb_rate_est || tca[TCA_RATE]) {
+ err = gen_new_estimator(&cl->bstats, &cl->rate_est,
+ qdisc_root_sleeping_lock(sch),
+ tca[TCA_RATE] ? : &est.nla);
+ if (err) {
+ kfree(cl);
+ goto failure;
+ }
}
cl->refcnt = 1;