igb interrupt moderation

[Michael Tüxen]

On Jan 3, 2010, at 6:35 PM, Barney Cordoba wrote:

> --- On Sun, 1/3/10, Michael Tüxen <Michael.Tuexen at lurchi.franken.de> wrote:
> 
>> From: Michael Tüxen <Michael.Tuexen at lurchi.franken.de>
>> Subject: Re: igb interrupt moderation
>> To: "Barney Cordoba" <barney_cordoba at yahoo.com>
>> Cc: freebsd-net at freebsd.org, "Mike Tancsa" <mike at sentex.net>
>> Date: Sunday, January 3, 2010, 12:14 PM
>> On Jan 3, 2010, at 6:00 PM, Barney
>> Cordoba wrote:
>> 
>>> 
>>> 
>>> --- On Sun, 1/3/10, Michael Tüxen <Michael.Tuexen at lurchi.franken.de>
>> wrote:
>>> 
>>>> From: Michael Tüxen <Michael.Tuexen at lurchi.franken.de>
>>>> Subject: Re: igb interrupt moderation
>>>> To: "Mike Tancsa" <mike at sentex.net>
>>>> Cc: "Barney Cordoba" <barney_cordoba at yahoo.com>,
>> jfvogel at gmail.com,
>> freebsd-net at freebsd.org
>>>> Date: Sunday, January 3, 2010, 11:38 AM
>>>> On Jan 3, 2010, at 5:23 PM, Mike
>>>> Tancsa wrote:
>>>> 
>>>>> At 11:13 AM 1/3/2010, Michael Tüxen wrote:
>>>>>>> 
>>>>>>> Just a separate datapoint about this
>> driver,
>>>> unless I apply
>>>>>>> 
>>>>>>> http://people.freebsd.org/~yongari/igb/igb.buf.patch6
>>>>>>> 
>>>>>>> the driver is not really usable for me
>> in
>>>> RELENG_8 on the dual port version of the card
>>>>>> Could you elaborate on what you mean by
>> "not
>>>> really usable"?
>>>>> 
>>>>> 
>>>>> Hi,
>>>>>          Some
>> link state issues
>>>> (getting confused about what port is up), problems
>> at high
>>>> packet rates.  I dont have this card in
>> production, but
>>>> in my test environment it was much more stable on
>> RELENG_8
>>>> with the above patch in that I was not able to
>> wedge the
>>>> box.  pps rates were pretty ok on a low end
>> i7 as
>>>> well.
>>>> Thanks for the information. I'll give it a try. I
>> have a
>>>> problem when I flood
>>>> a system with SCTP INITs. The system under attack
>> becomes
>>>> completely unresponsive
>>>> on the console. However, it continues to send
>> INIT-ACKs
>>>> back. After the last
>>>> commit from Jack it recovers after the attack. Not
>> yet sure
>>>> what is going on.
>>>> Using the em driver does not have the problem.
>> However,
>>>> when using the em
>>>> driver only one core is fully used, when using the
>> igb
>>>> driver both cores are fully
>>>> used. Unfortunately I do not have a more than dual
>> core
>>>> machine available for
>>>> this testing...
>>> 
>>> Try em and lower the interrupt moderation to something
>> like 500 (about
>>> 100 packets per int is good). The latency isn't going
>> to be noticable and
>>> you'll see your cpu burden reduced quite a bit. 
>> I'll try. Thanks.
>>> 
>>> Are you using a single NIC on a server, or do you have
>> a firewall or
>>> bridge?
>> The system is a sender/receiver for SCTP. I'm interested in
>> the 82576
>> since it provides checksum offloading for it. I use one or
>> two ports
>> for simultaneous data transfer. The cards using the em
>> driver do
>> not support this feature. So I'm trying to verify that the
>> performance
>> goes up when using hardware checksum. But under attack,
>> this is currently
>> not the case... 
>>> 
>>> Barney
> 
> I usually try to find something that actually works before I worry
> about special features. But we all work differently.
... I want to make sure that the SCTP stuff works. So others
can "just use it". SCTP checksum offloading is one important
feature...
> 
> Barney
> 
> 
> 
>