On Tue, 3 Jan 2006, Stephen Hemminger wrote:
> On Wed, 28 Dec 2005 22:35:50 -0500
> Bill Fink <[EMAIL PROTECTED]> wrote:
>
> > Would the following patch be at all useful for the 2.6.14.x stable
> > series, since enabling TSO there causes a 40% or greater TCP performance
> > penalty, or is 2.6.15 final so imminenent that it wouldn't be
> > considered useful?
> >
> > Signed-off-by: Bill Fink <[EMAIL PROTECTED]>
> >
> > --- linux-2.6.14.3.orig/drivers/net/ixgb/ixgb_main.c 2005-11-24
> > 17:10:21.000000000 -0500
> > +++ linux-2.6.14.3/drivers/net/ixgb/ixgb_main.c 2005-12-28
> > 01:06:05.000000000 -0500
> > @@ -445,7 +445,8 @@
> > NETIF_F_HW_VLAN_RX |
> > NETIF_F_HW_VLAN_FILTER;
> > #ifdef NETIF_F_TSO
> > - netdev->features |= NETIF_F_TSO;
> > + /* TSO not performant at present - disable by default */
> > + netdev->features &= ~NETIF_F_TSO;
> > #endif
> >
> > if(pci_using_dac)
>
> doesn't make sense to patch just one driver. It would make more sense
> to backport the TSO cwnd patch from 2.6.15
I agree but I don't currently have the knowledge or time to do that,
and it's probably moot since I believe 2.6.15 final is now out.
Also, I suspect it's really only an issue for 10-GigE NICs. Testing
with an Intel quad-GigE NIC didn't show any problem:
[EMAIL PROTECTED] ifconfig eth5
eth5 Link encap:Ethernet HWaddr 00:04:23:08:8A:46
inet addr:192.168.5.75 Bcast:192.168.5.255 Mask:255.255.255.0
inet6 addr: fe80::204:23ff:fe08:8a46/64 Scope:Link
UP BROADCAST RUNNING MULTICAST MTU:9000 Metric:1
...
[EMAIL PROTECTED] ethtool -k eth5
Offload parameters for eth5:
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp segmentation offload: on
(and likewise on chance4 (192.168.5.78))
TSO enabled:
chance% nuttcp -w1m 192.168.5.78
1183.7128 MB / 10.03 sec = 989.7925 Mbps 11 %TX 8 %RX
chance% nuttcp -r -w1m 192.168.5.78
1183.7982 MB / 10.03 sec = 989.7653 Mbps 11 %TX 8 %RX
[EMAIL PROTECTED] ethtool -K eth5 tso off
[EMAIL PROTECTED] ethtool -k eth5
Offload parameters for eth5:
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp segmentation offload: off
(and likewise on chance4 (192.168.5.78))
TSO disabled:
chance% nuttcp -w1m 192.168.5.78
1182.5833 MB / 10.02 sec = 989.7864 Mbps 13 %TX 8 %RX
chance% nuttcp -r -w1m 192.168.5.78
1182.1543 MB / 10.02 sec = 989.5802 Mbps 12 %TX 8 %RX
-Bill
P.S. I can't currently get to www.kernel.org, getting the following error:
Forbidden
You don't have permission to access / on this server.
Additionally, a 404 Not Found error was encountered while trying to use an
ErrorDocument to handle the request.
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