net_sched: htb: do not setup default rate estimators (64153ce0) · Commits · 戴 / test

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>

net/sched/sch_htb.c

+12 −6

Original line number	Diff line number	Diff line
		@@ -65,6 +65,10 @@ static int htb_hysteresis __read_mostly = 0; /* whether to use mode hysteresis f
		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 */
		@@ -1366,6 +1370,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
		if (!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);
		@@ -1373,6 +1378,7 @@ static int htb_change_class(struct Qdisc *sch, u32 classid,
		kfree(cl);
		goto failure;
		}
		}

		cl->refcnt = 1;
		cl->children = 0;

Admin message