lkml.org 
[lkml]   [2010]   [Aug]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
DateThu, 26 Aug 2010 08:43:42 -0600 (Mountain Daylight Time)
FromMarc Aurele La France <>
SubjectRe: RFC: MTU for serving NFS on Infiniband
On Thu, 26 Aug 2010, Eric Dumazet wrote:
> Le jeudi 26 août 2010 à 05:40 -0600, Marc Aurele La France a écrit :

>> Steady now. There's no need to YELL nor be arrogant. You and I both know
>> there's a place for NFS over UDP. That's not changing any time soon. While
>> I'm aware of the issue you brought up, it is separate from the one at hand in
>> this discussion.

>> I do want to thank you, however, for reminding me of TCP. It's something
>> 20/20 hindsight says I should have checked out before starting this thread.
>> Logistically, it'll be a few days before I can do so though. If that allows
>> me to increase the MTU all the way up to 65520, then this UDP thing will
>> likely remain unresolved.

> Unfortunately, your infiniband device lacks NETIF_F_SG support.

Oh, the device itself probably has something similar, but ipoib
(IP-over-Infiniband) doesn't export that capability.

> MTU a bit larger than PAGE_SIZE-overhead will need high order
> allocations ?

Right. And a 65520 MTU allocates sk_buff's with 128K contiguous payloads.

Marc.

+----------------------------------+----------------------------------+
| Marc Aurele La France | work: 1-780-492-9310 |
| Academic Information and | fax: 1-780-492-1729 |
| Communications Technologies | email: tsi@ualberta.ca |
| 352 General Services Building +----------------------------------+
| University of Alberta | |
| Edmonton, Alberta | Standard disclaimers apply |
| T6G 2H1 | |
| CANADA | |
+----------------------------------+----------------------------------+
\
 
 \ /
  Last update: 2010-08-26 16:47    [from the cache]
©2003-2010