freebsd stable - Mar 2006 - jumbo em

Hello 

I have 2 freebsd servers connected by dedicated wire via em interfaces.
systems = 6.1-PRERELEASE #0: Tue Mar 14 11:58:23 MSK 2006

1st)
man em says
MTU size for Jumbo Frames is 16114 and i'm sure i've setup this on
freebsd-5 and probably ealier 6.0
But now 
 ifconfig em1 mtu 16114
ifconfig: ioctl (set mtu): Invalid argument
16110 - max possible

2nd) 
Seems ok with mss 
13:59:36.590411 IP 10.0.0.1.31408 > 10.0.0.2.22: S 3543827971:3543827971(0)
win 65535 <mss 16070,nop,wscale 0,nop,nop,timestamp[|tcp]>
13:59:36.590462 IP 10.0.0.2.22 > 10.0.0.1.31408: S 3003760814:3003760814(0)
ack 3543827972 win 65535 <mss 16070,nop,wscale 0,nop,nop,timestamp[|tcp]>
seems jumbo working
but 
983/652/1635 mbufs in use (current/cache/total)
908/410/1318/25600 mbuf clusters in use (current/cache/total/max)
908/329 mbuf+clusters out of packet secondary zone in use (current/cache)
0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
2061K/983K/3044K bytes allocated to network (current/cache/total)
0/14496/3371 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
54/129/6656 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
23799 requests for I/O initiated by sendfile
107 calls to protocol drain routines

thereis empty info about jumbos. Is it ok?

Jura

On 3/16/06, Yuriy N. Shkandybin <jura@networks.ru>
wrote:
> Hello
>
> I have 2 freebsd servers connected by dedicated wire via em interfaces.
> systems = 6.1-PRERELEASE #0: Tue Mar 14 11:58:23 MSK 2006
>
> 1st)
> man em says
> MTU size for Jumbo Frames is 16114 and i'm sure i've setup this on
freebsd-5 and probably ealier 6.0
> But now
>  ifconfig em1 mtu 16114
> ifconfig: ioctl (set mtu): Invalid argument
> 16110 - max possible
With newer hardware the FIFO has been getting smaller, so jumbos
even this large wont be allowed, I'm away from the code right now
but on the 82571 adapter its max is in the 9K range.

And the man page is more than likely out of date.

Whether you can do jumbos at all, and if so, what size you are allowed
to make them is adpater specific.

Jack