From: Jarek Poplawski <jarkao2@gmail•com>
To: Linux Networking Mailing List <netdev@vger•kernel.org>
Cc: Sami Farin <safari-kernel@safari•iki.fi>
Subject: Re: Linux 2.6.27.5 / SFQ/HTB scheduling problems
Date: Fri, 14 Nov 2008 07:21:14 +0000 [thread overview]
Message-ID: <20081114072114.GA4408@ff.dom.local> (raw)
In-Reply-To: <20081113142958.36pzkmzwtxd3wbox@m.safari.iki.fi>
On 13-11-2008 15:29, Sami Farin wrote:
...
> Oh, I had old ethtool..
> These with v 6:
>
> # ethtool -k eth0
> Offload parameters for eth0:
> rx-checksumming: off
> tx-checksumming: off
> scatter-gather: off
> tcp segmentation offload: off
> udp fragmentation offload: off
> generic segmentation offload: on
>
> Wow. I turned gso off and now it works just like before.
> No packets over size of mtu anymore, either.
>
> State Recv-Q Send-Q Local Address:Port Peer Address:Port
> ESTAB 0 122334 80.223.84.180:57694 74.54.226.166:80 timer:(on,4.475ms,0) uid:518 ino:4546485 sk:2ea3ac80ffff8800
> ts sackcubic wscale:8,3 rto:4499 rtt:2914.12/378.5 cwnd:134 ssthresh:30 send 522.4Kbps rcv_space:5728
>
> --- 84.250.192.1 ping statistics ---
> 50 packets transmitted, 50 received, 0% packet loss, time 1877ms
> rtt min/avg/max/mdev = 22.463/38.354/99.126/13.738 ms, pipe 3, ipg/ewma 38.309/34.963 ms
>
> ...
>> Anyway these TSO/GSO/jumbo_frames are usually bad idea with packet
>> schedulers (or need more tweaking - e.g. sfq quantum).
>
> Well this GSO on by default was an unexpected surprise for me, for sure.
>
> Maybe a warning on htb (or something) module load
> "GSO enabled, everything might not work as expected, try
> 'ethtool -K eth0 gso off' to turn GSO off"..? ;)
I agree, such a warning could be useful.
BTW, r2q == 1 in your config could harm latency too; if it's because
of quantum warnings, usually (if there are big rate differences
between classes) it's better to use htb class's "quantum" parameter
(tc class add htb help).
Jarek P.
PS: it seems your mailer setting prevents adding your email as "To:"
while doing "Reply All". Sometimes it's intended, but not the most
popular on this list (e.g. I'd prefer to be "To/Cc-ed", because I'm
not a subscriber at the moment).
prev parent reply other threads:[~2008-11-14 7:21 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-11-11 15:17 Linux 2.6.27.5 / SFQ/HTB scheduling problems Sami Farin
2008-11-11 21:47 ` Sami Farin
2008-11-13 7:15 ` Jarek Poplawski
2008-11-13 11:48 ` Sami Farin
2008-11-13 13:59 ` Jarek Poplawski
2008-11-13 14:29 ` Sami Farin
2008-11-14 7:21 ` Jarek Poplawski [this message]
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