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Commit 64153ce0 authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 130d3d68

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;