Re: Ethernet auto-select and concurrent 10, 100 and 1000 connections

[Sad Clouds <cryintothebluesky%gmail.com@localhost>]

On Mon, 4 Feb 2019 20:45:13 +0000
Mike Pumford <mpumford%mudcovered.org.uk@localhost> wrote:

> On 03/02/2019 12:07, Sad Clouds wrote:
> > On Sun, 3 Feb 2019 11:27:07 +0100
> > tlaronde%polynum.com@localhost wrote:
> > 
> >> With all your help and from this summary, I suspect that the
> >> probable culprit is 3) above (linked also to 2) but mainly 3): an
> >> instance of Samba, serving a 10T or a 100T request is blocking on
> >> I/O,
> > 
> > You must have some ancient hardware that is not capable of utilising
> > full network bandwidth.
> > 
> > I have Sun Ultra10 with 440MHz CPU, this has a 1000baseT PCI network
> > card, but when sending TCP data it can only manage around 13
> > MiB/sec. Looking at 'vmstat 1' output it is clear that CPU is 100%
> > busy, 50% system + 50% interrupt.
> > 
> > ultra10$ ifconfig wm0
> > wm0: flags=0x8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
> >          capabilities=2bf80<TSO4,IP4CSUM_Rx,IP4CSUM_Tx,TCP4CSUM_Rx>
> >          capabilities=2bf80<TCP4CSUM_Tx,UDP4CSUM_Rx,UDP4CSUM_Tx,TCP6CSUM_Tx>
> >          capabilities=2bf80<UDP6CSUM_Tx>
> >          enabled=0
> Any reason you aren't using the hardware offload capability of this 
> interface? The card supports checksum ofloading for v4 &v6 frames and 
> also the ofloading of some of the TCP stack work for V4 this might
> help your performance. Loogking at this output I'd suggest adding the 
> following to your ifconfig.wm0 file:
> tso4 ip4csum tcp4csum
> 
> Not exactly sure on the options for the V6 stuff (check the ifconfig
> man page). My wm card has more v6 offload so I don't think the v6
> options I use would work.
> 
> I suspect the offload would give you more of a boost than on my
> 2-4GHz amd64 systems but even on those its quit noticable the
> difference that turning these on makes.
> 
> Mike

I've tried those options before, but performance gain was marginal
compared to gigabit ethernet speeds, i.e. it went up from 13 MiB/sec to
around 17 MiB/sec. But I guess 30% gain is better than nothing.

I think Sun Ultra10 has 32-bit 33 MHz PCI bus, so in theory it has
bandwidth for 133 MiB/sec. Not sure why there is such high CPU usage
on this system when copying data via the network card. OK it's a very
old system, but I was expecting less overhead.