From: Jeff Garzik <jgarzik@pobox.com>
To: Ben Greear <greearb@candelatech.com>
Cc: "Feldman, Scott" <scott.feldman@intel.com>,
netdev@oss.sgi.com, ricardoz@us.ibm.com
Subject: Re: [e1000 2.6 10/11] TxDescriptors -> 1024 default
Date: Thu, 11 Sep 2003 15:59:31 -0400 [thread overview]
Message-ID: <3F60D423.4040005@pobox.com> (raw)
In-Reply-To: <3F60D0F3.8080006@candelatech.com>
Ben Greear wrote:
> Jeff Garzik wrote:
>
>> Feldman, Scott wrote:
>>
>>> * Change the default number of Tx descriptors from 256 to 1024.
>>> Data from [ricardoz@us.ibm.com] shows it's easy to overrun
>>> the Tx desc queue.
>>
>>
>>
>>
>> All e1000 patches applied except this one.
>>
>> Of _course_ it's easy to overrun the Tx desc queue. That's why we
>> have a TX queue sitting on top of the NIC's hardware queue. And TCP
>> socket buffers on top of that. And similar things.
>>
>> Descriptor increases like this are usually the result of some
>> sillyhead blasting out UDP packets, and then wondering why he sees
>> packet loss on the local computer (the "blast out packets" side).
>
>
> Erm, shouldn't the local machine back itself off if the various
> queues are full? Some time back I looked through the code and it
> appeared to. If not, I think it should.
Given the guarantees of the protocol, the net stack has the freedom to
drop UDP packets, for example at times when (for TCP) one would
otherwise queue a packet for retransmit.
Jeff
next prev parent reply other threads:[~2003-09-11 19:59 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-09 3:14 [e1000 2.6 10/11] TxDescriptors -> 1024 default Feldman, Scott
2003-09-11 19:18 ` Jeff Garzik
2003-09-11 19:45 ` Ben Greear
2003-09-11 19:59 ` Jeff Garzik [this message]
2003-09-11 20:12 ` David S. Miller
2003-09-11 20:40 ` Ben Greear
2003-09-11 21:07 ` David S. Miller
2003-09-11 21:29 ` Ben Greear
2003-09-11 21:29 ` David S. Miller
2003-09-11 21:47 ` Ricardo C Gonzalez
2003-09-11 22:00 ` Jeff Garzik
2003-09-11 22:15 ` Ben Greear
2003-09-11 23:02 ` David S. Miller
2003-09-11 23:22 ` Ben Greear
2003-09-11 23:29 ` David S. Miller
2003-09-12 1:34 ` jamal
2003-09-12 2:20 ` Ricardo C Gonzalez
2003-09-12 3:05 ` jamal
2003-09-13 3:49 ` David S. Miller
2003-09-13 11:52 ` Robert Olsson
2003-09-15 12:12 ` jamal
2003-09-15 13:45 ` Robert Olsson
2003-09-15 23:15 ` David S. Miller
2003-09-16 9:28 ` Robert Olsson
2003-09-14 19:08 ` Ricardo C Gonzalez
2003-09-15 2:50 ` David Brownell
2003-09-15 8:17 ` David S. Miller
2004-05-15 12:14 ` TxDescriptors -> 1024 default. Please not for every NIC! Marc Herbert
2004-05-19 9:30 ` Marc Herbert
2004-05-19 10:27 ` Pekka Pietikainen
2004-05-20 14:11 ` Luis R. Rodriguez
2004-05-20 16:38 ` [Prism54-devel] " Jean Tourrilhes
2004-05-20 16:45 ` Tomasz Torcz
2004-05-20 17:13 ` zero copy TX in benchmarks was " Andi Kleen
2004-05-19 11:54 ` Andi Kleen
[not found] <3F60DE5B.1010700@pobox.com>
2003-09-11 21:27 ` [e1000 2.6 10/11] TxDescriptors -> 1024 default Ricardo C Gonzalez
-- strict thread matches above, loose matches on Subject: below --
2003-09-12 5:13 Feldman, Scott
2003-09-12 12:44 ` jamal
2003-09-12 15:29 ` Donald Becker
2003-09-12 17:44 ` Ricardo C Gonzalez
2003-09-15 11:37 ` jamal
2003-09-12 18:12 ` Ben Greear
2003-09-12 18:31 ` Ricardo C Gonzalez
2003-09-15 11:29 ` jamal
[not found] <Pine.LNX.4.58.0405141430340.4622@fcat>
2004-05-18 14:34 ` Ricardo C Gonzalez
2004-06-02 19:11 ` Marc Herbert
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