From: Patrick McHardy <kaber@trash.net>
To: Stephen Hemminger <shemminger@osdl.org>
Cc: "David S. Miller" <davem@davemloft.net>, netdev@oss.sgi.com
Subject: Re: [PATCH] netem: account for packets in delayed queue in qlen
Date: Tue, 05 Apr 2005 21:48:45 +0200 [thread overview]
Message-ID: <4252EB9D.9070305@trash.net> (raw)
In-Reply-To: <20050329152110.38d50653@dxpl.pdx.osdl.net>
Stephen Hemminger wrote:
> Netem has a private queue for delayed packets, and currently, packets
> in this queue are not accounted for in the qdisc qlen statistics.
> This is a problem if netem is used inside another qdisc doing rate
> control that peeks at the qlen.
>
> This patch changes the statistics to include the packets held but
> not ready to send.
There is one troublesome spot left, netem_watchdog() decreases q.qlen
when the packet couldn't be enqueued. I don't think it is possible
to make netem useable as leaf-qdisc, it will always have to touch
q.qlen from timer context and classful qdiscs can't deal with this
since they all maintain their own q.qlen counters and expect changes
only in the +-1 range in enqueue/dequeue/requeue/drop. Best thing IMO
would be to refuse to work as anything but root qdisc.
Regards
Patrick
next prev parent reply other threads:[~2005-04-05 19:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-03-29 23:21 [PATCH] netem: account for packets in delayed queue in qlen Stephen Hemminger
2005-04-01 4:36 ` David S. Miller
2005-04-05 19:48 ` Patrick McHardy [this message]
2005-04-05 19:58 ` Stephen Hemminger
2005-04-07 19:04 ` Stephen Hemminger
2005-04-17 15:38 ` Patrick McHardy
2005-04-19 1:06 ` Stephen Hemminger
2005-04-20 14:00 ` Patrick McHardy
2005-04-21 3:20 ` Stephen Hemminger
2005-04-21 23:10 ` Patrick McHardy
2005-04-21 23:22 ` Stephen Hemminger
2005-04-21 23:39 ` Patrick McHardy
2005-04-22 0:05 ` jamal
2005-04-22 0:10 ` Patrick McHardy
2005-04-22 0:32 ` jamal
2005-04-22 0:40 ` jamal
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