Re: Fw: hfsc and huge set of rules

[Tomasz Paszkowski <tomasz.paszkowski@e-wro.pl>]

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On Fri, Jul 30, 2004 at 12:34:49PM +0200, Patrick McHardy wrote:
> David S. Miller wrote:
> >Looks like qdisc destruction has some expensive algorithms.
> >Any quick ideas about the root culprit at least in the hfsc
> >case?  He says htb does it too.
> 
> hfsc_destroy_qdisc takes O(n) time wrt. the number of classes,
> but 5-6 seconds is still long. If all these classes contain inner
> qdiscs other than the default, I guess removing the classes from
> dev->qdisc_list in qdisc_destroy takes up most of the time, with
> n O(n) operations. The __qdisc_destroy rcu callback also calls
> reset before destroy, I don't know any qdisc where this is really
> neccessary. Without inner qdiscs, I need to see the script first to
> judge what's going wrong. Tomasz ?

http://www.e-wro.pl/~acid/tc.batch.gz. In my opinion it's not the case
of expensive algorithms, but the number of classes. With this rule set loaded
(tc -b tc.batch) command:

for i in 'e1.903 e0.930 e0.931 e0.932' ; do
	tc qdisc del dev ${i} root
done
completly freezes machine for about 5-6 seconds.

I was trying do modify the code od hfsc_qdisc_destroy scheduling another
task using schedule_task (), but i don't have enough knowledge to do deal
with proper locking of qdisc structures.

-- 
Tomasz Paszkowski

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