[LARTC] Re: some can help out with u32 & TBF limitation < 2048 only

[Trevor Warren <trevorwarren@softhome.net>]

Thanks for the same martin. Am working on the same and will send the
results of the script back to the list.

Trevor


On Thu, 2003-07-03 at 13:42, devik wrote:
> I just looked into u32 source and sent
> mail to Alexey regarding some internals.
> But at this time I can observe some things:
> 
> 1) if you don't specify handle for u32 filter, new one will
>    be assigned from NODE range (0-0x7ff)|0x800. Here you
>    have 2048 limit probably.
> 
> 2) even with 2000 classes it will be slow as for each packet
>    all 2000 filers are looked-up linearly.
> 
> To speed it up and make the range greater you need to use
> hashing ability of u32 (see divisor parameter). Then you
> can use last byte in IP as hash value and use up to 2048
> sub-filters per such byte.
> Thus you can simply extend range to 500.000 filters. If
> you assign some node ids manually then to 1.000.000.
> 
> I'd suggest you to use 2 level hash table instead. It will
> allow you to hash on 16bits of IP address (65.000 classes)
> and it will be 2000times faster than your current approach.
> See u32 manual (maybe on lartc?) on how to setup hash
> tables ...
> 
> I hope I didn't make mistake in my ideas - maybe Alexey
> will correct it.
> 
> -------------------------------
>     Martin Devera aka devik
> Linux kernel QoS/HTB maintainer
>   http://luxik.cdi.cz/~devik/
> 
> On 2 Jul 2003, Trevor Warren wrote:
> 
> >
> > Hello Folks,
> >
> >  Some time ago i posted a mail on this list regarding the traffic
> > shaping script i devised based on htb and u32. The limitations of which
> > are 2048 filters + htb classes.
> >
> >  I am in a deep fix without a resolution for the same. HTB is really
> > cewl as it delivers on its functionality, but this lack of scalability
> > issue is a pain in me **** cause of which some server deployments are on
> > hold.
> >
> >  Thanks in advance and would be glad to hear from anyone. The resolution
> > for the same when i find out i will post it on the mailing list.
> >
> > Trevor
> >
> >
> > --
> > ( >-        LINUX, It's all about CHOICE      -< )
> > /~\    __        twarren@redhat.com       __   /~\
> > |  \) /  Pre Sales Consultant - Red Hat     \ (/ |
> > |_|_  \    9820349221(M) | 22881326(O)      / _|_|
> >        \___________________________________/
> >
-- 
( >-        LINUX, It's all about CHOICE      -< )
/~\    __        twarren@redhat.com       __   /~\
|  \) /  Pre Sales Consultant - Red Hat     \ (/ |
|_|_  \    9820349221(M) | 22881326(O)      / _|_|
       \___________________________________/

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