Fabien Salvi wrote:
>
> >
> > It already looks like there are 50% fewer interrupts to the CPU. Now that
> > could be because the FC pkts are larger than the GigE. Were you using Jumbo
> > frames for GigE? How different are the FC pkts, in terms of size?
>
> yes, MTU for GigE is 1500 and for FC 4096
> I've tried to decrease MTU on FC to 2000 or to increase to 8192, but
> each time, the transfer was a half of the maximum (10 MB/s).
>
> > By the way, is the FTP a read or a write? That is, is it TX traffic or RX
> > traffic on the nodes? You might *not* want to ignore the lesser CPU
> > utilization and fewer interrupts observation. That might hold the key.
> >
> > Is it also possible to test the network bandwidth independent of any disk
> > I/O on the servers? This will narrow down the number of variables in the
> > system.
>
> Yes you're right.
> I'm going to do some tests with ramdisks to prevent perturbation of I/O
> traffic...
So, here are the results :
I can't use jumbo frames on GigE because my NICs don't it.
I use ramdisk and performance are the following :
- around 45MB/s with GigE
- around 22MB/s with IPoFC
So, I have a little improvement for GigE but not really for IP over
FC...
It's the same in Tx or Rx and for put/get in FTP.
--
Fabien SALVI Centre de Ressources Informatiques
Archamps, France -- http://www.cri74.org
PingOO GNU/linux distribution : http://www.pingoo.org
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