Re: Network slowdown from 2.6.7 to 2.6.9

J.A. Magallon
2004-11-23T23:43:52Z

On 2004.11.23, Stephen Hemminger wrote:
> On Mon, 22 Nov 2004 15:38:16 -0800
> Harry Edmon <harry@atmos.washington.edu> wrote:
>
> > Tried them all - none of them helped. Use "ntop" I can see that my
> > throughput on the Intel gigabit ethernet interface on the system maxes
> > out at 15.2 Mbps with 2.6.9. With 2.6.7 it made it to 35 Mbps.
> >
> > Does anyone have any other suggestions as to what to look for to
> > diagnose this problem?
>
> Well, before the TSO changes, if TSO was enabled then TCP would not obey slow
> start or do congestion control properly. Did you increase the TCP send/receive
> buffers (sysctl's net.ipv4.tcp_rmem and net.ipv4.tcp_wmem)? You may just
> be window limited. Also, 2.6.9 has TCP bugs with TSO that can cause panic's.
> These have been fixed in 2.6.10-rc2.
>

With two 2.6.9 boxes (really, 2.6.9-mm1 and 2.6.9-bproc), I get this:

nada:~> iperf -s
------------------------------------------------------------
Server listening on TCP port 5001
TCP window size: 85.3 KByte (default)
------------------------------------------------------------
[ 4] local 155.210.155.215 port 5001 connected with 155.210.155.212 port 41695
[ ID] Interval Transfer Bandwidth
[ 4] 0.0-10.0 sec 112 MBytes 94.0 Mbits/sec
annwn:/proc/sys/net> iperf -c nada
------------------------------------------------------------
Client connecting to nada, TCP port 5001
TCP window size: 16.0 KByte (default)
------------------------------------------------------------
[ 3] local 155.210.155.212 port 41695 connected with 155.210.155.215 port 5001
[ ID] Interval Transfer Bandwidth
[ 3] 0.0-10.0 sec 112 MBytes 94.0 Mbits/sec

So 94 Mbits/sec, through 100Mb ether. So parhaps the netsork layer
is not the culprit, just the driver.

BTW:

I'm getting an oops with 2.6.9 that ends on a call to skb_clone,
using e1000. Is this what you refer to ?

If the answer is yes, do you have any pointer to a patch to fix just
this ? I would prefer an individual patch instead of full -bk, because
I use 2.6.9+bproc, and probably bproc wont patch against -bk.

TIA.

--
J.A. Magallon <jamagallon()able!es> \ Software is like sex:
werewolf!able!es \ It's better when it's free
Mandrakelinux release 10.2 (Cooker) for i586
Linux 2.6.10-rc2-jam3 (gcc 3.4.1 (Mandrakelinux 10.1 3.4.1-4mdk)) #1