From: Jarek Poplawski <jarkao2@gmail.com>
To: Denys Fedoryschenko <denys@visp.net.lb>
Cc: netdev@vger.kernel.org, Stephen Hemminger <shemminger@vyatta.com>
Subject: Re: Fwd: iproute2 wrong burst/cburst calculation?
Date: Wed, 21 Jan 2009 09:48:43 +0000 [thread overview]
Message-ID: <20090121094843.GA5140@ff.dom.local> (raw)
In-Reply-To: <200901202257.11773.denys@visp.net.lb>
On Tue, Jan 20, 2009 at 10:57:11PM +0200, Denys Fedoryschenko wrote:
...
> class htb 1:3 parent 1:2 leaf 3: prio 0 quantum 200000 rate 680000Kbit ceil
> 950000Kbit burst 1445b/8 mpu 0b overhead 0b cburst 1425b/8 mpu 0b overhead 0b
> level 0
> Sent 140533370 bytes 200327 pkt (dropped 0, overlimits 0 requeues 0)
> rate 52228Kbit 9289pps backlog 0b 0p requeues 0
> lended: 199720 borrowed: 607 giants: 0
> tokens: 17 ctokens: 12
>
> So just look: 1:3 have burst 1445 / 1425, and 1:2, his parent - burst 1425 and
> cburst 1425. It is wrong? I am not so experienced in htb to judge, but i feel
> like iproute2 calculating burst/cburst not right way.
...
> I guess it was supposed in this formula, that size must vary, and higher rate
> must have higher size. But because our timer resolution so high, and we add
> also mtu value... things going wrong.
> I dont know yet, how to calculate this correctly. Even not sure if it is
> wrong. But HTB author, stated clearly
Denys, I can't verify this all anytime soon, but most likely you are
right. Lower burst/cburst for higher rates means there have to be some
overflow, but since I think you know tc better than me, probably a
patch is needed. (Then one of possible "fast" fixes could be probably
to check for some max rate which doesn't overflow yet.)
Thanks,
Jarek P.
prev parent reply other threads:[~2009-01-21 9:48 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-01-20 20:57 Fwd: iproute2 wrong burst/cburst calculation? Denys Fedoryschenko
2009-01-21 9:48 ` Jarek Poplawski [this message]
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