Venkat
Your assessment of the IB vs. Ethernet latencies isn't necessarily
correct.
- you already have available low latency 10GE switches (< 1us
port-to-port)
- you already have available low latency (cut-through processing) 10GE
TOE engines
The Veritest verified 10GE TOE end-to-end latency is < 10us today
(end-to-end being from a Linux user-space-process to a Linux
user-space-process through a switch; full report with detail of the
setup is available at
http://www.chelsio.com/technology/Chelsio10GbE_Fujitsu.pdf)
For comparison: the published IB latency numbers are around 5us today
and those use a polling receiver, and those don't include a context
switch(es) as does the Ethernet number quoted above.
'Asgeir
> -----Original Message-----
> From: netdev-bounce@xxxxxxxxxxx [mailto:netdev-bounce@xxxxxxxxxxx] On
> Behalf Of jaganav@xxxxxxxxxx
> Sent: Thursday, March 31, 2005 5:49 PM
> To: H. Peter Anvin
> Cc: Roland Dreier; Dmitry Yusupov; open-iscsi@xxxxxxxxxxxxxxxx; David
S.
> Miller; mpm@xxxxxxxxxxx; andrea@xxxxxxx; michaelc@xxxxxxxxxxx;
> James.Bottomley@xxxxxxxxxxxxxxxxxxxxx; ksummit-2005-discuss@xxxxxxxxx;
> netdev@xxxxxxxxxxx; Benjamin LaHaise
> Subject: Re: Linux support for RDMA
>
> Quoting "H. Peter Anvin" <hpa@xxxxxxxxx>:
> > Benjamin LaHaise wrote:
> > >
> > > I'm curious how the 10Gig ethernet market will pan out. Time and
> again
> > > the market has shown that ethernet always has the cost advantage
in
> the
> > > end. If something like Intel's I/O Acceleration Technology makes
it
> > > that much easier for commodity ethernet to achieve similar
performance
> > > characteristics over ethernet to that of IB and fibre channel, the
> cost
> > > advantage alone might switch some new customers over. But the
> hardware
> > > isn't near what IB offers today, making IB an important niche
filler.
> > >
> >
> > From what I've seen coming down the pipe, I think 10GE is going to
> > eventually win over IB, just like previous generations did over
Token
> > Ring, FDDI and other niche filler technologies. It doesn't, as you
say,
> > mean that e.g. IB doesn't matter *now*; furthermore, it also matters
for
> > the purpose of fixing the kind of issues that are going to have to
be
> > fixed anyway.
> >
> > -hpa
> >
> >
> >
>
> No doubt, Ethernet will eventually win .. btw, Hasn't history proven
this
> over
> ATM? More specifically when the industry predicted that ATM will
replace
> ethernet :)
>
> However, I'll have to agree with Ben that IB technolgy will fill an
> important
> niche segment, more specifically so in the low end of High Performance
> Computing
> (HPC) segment which is in a transition mode currently moving away from
> proprietary interconnects to industry standards based IB technology.
> Eventhough,
> ethernet may eventually may catch up with IB in terms of the bandwidth
but
> IB
> fabrics can offer better latencies.
>
> Thanks
> Venkat
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