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| author | Eric Dumazet <edumazet@google.com> | 2013-06-06 14:53:16 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2013-06-12 00:14:21 -0700 |
| commit | 64153ce0a7b61b2a5cacb01805cbf670142339e9 (patch) | |
| tree | f5c854262ef7e05271151391debac6aecad110b0 /net/sched | |
| parent | 130d3d68b52097c7ae081109f700b02776adcb9c (diff) | |
| download | lwn-64153ce0a7b61b2a5cacb01805cbf670142339e9.tar.gz lwn-64153ce0a7b61b2a5cacb01805cbf670142339e9.zip | |
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>
Diffstat (limited to 'net/sched')
| -rw-r--r-- | net/sched/sch_htb.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/net/sched/sch_htb.c b/net/sched/sch_htb.c index 162fb800754c..1a3655a606c1 100644 --- a/net/sched/sch_htb.c +++ b/net/sched/sch_htb.c @@ -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 */ @@ -1366,12 +1370,14 @@ static int htb_change_class(struct Qdisc *sch, u32 classid, 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; |