[prev in list] [next in list] [prev in thread] [next in thread] 

List:       e1000-devel
Subject:    Re: [E1000-devel] Rx throughput of 82599 based niantic card on PCIe
From:       Lakshmana Reddy <lreddy () datadomain ! com>
Date:       2009-09-10 17:08:12
Message-ID: 4AA9327C.4010402 () datadomain ! com
[Download RAW message or body]

[Attachment #2 (multipart/alternative)]


Hi Waskiewicz,

Thanks for the information, that helps lot.

Regards,
Lakshmana

Waskiewicz Jr, Peter P wrote:
> On Wed, 9 Sep 2009, Lakshmana Reddy wrote:
>
>   
>> Hi,
>>
>> The Rx throughput of 82599 NIC on PCIe Gen1 limits to 6.5 and 7.5Gbps 
>> with mtu 1500 and 9000 respectively.
>> On PCIe Gen2 the throughput seems to be ok (reaches line rate). However, 
>> I should mention that, I dont have a PCIe Gen2 slot on the same machine 
>> but on a different machine with PCIe Gen2 the throughput is good (line 
>> rate).
>> Is this a known issue?
>>     
>
> Yes.  There is a hardware errata in 82599 on PCIe gen1 systems.  In a 
> nutshell, there are extra clocks in the PCIe block that chew up a 
> percentage of the bus bandwidth, which ultimately limits the throughput of 
> the NIC.  These extra "dead" clocks are the errata.  There is nothing we 
> can do about it unfortunately.
>
> There are two recommendations here:
>
> 1) Run the 82599 in a Gen2 slot.
> 2) In your case, where you don't have a Gen2 slot in that box, use an 
> 82598, which has no trouble running at line rate in a Gen1 slot.
>
>   
>> Any help is greatly appreciated!
>>     
>
> Apologies that I don't have better news for you.
>
> Cheers,
> -PJ waskiewicz
>   


------------------------------------------------------------------------------
Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day 
trial. Simplify your report design, integration and deployment - and focus on 
what you do best, core application coding. Discover what's new with 
Crystal Reports now.  http://p.sf.net/sfu/bobj-july

_______________________________________________
E1000-devel mailing list
E1000-devel@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/e1000-devel


[prev in list] [next in list] [prev in thread] [next in thread]