rawio
[Top] [All Lists]

Re: Ping

To: bapper@xxxxxxxxxxxxxxx (Brian Pomerantz)
Subject: Re: Ping
From: slurn@xxxxxxxxxxxxxxxxxxxx (Scott Lurndal)
Date: Fri, 24 Mar 2000 15:56:45 -0800 (PST)
Cc: rawio@xxxxxxxxxxx
In-reply-to: <20000324154147.A22488@xxxxxxxxxxxxxxxxxxxxx> from "Brian Pomerantz" at Mar 24, 2000 03:41:47 PM
Sender: owner-rawio@xxxxxxxxxxx
> 
> On Fri, Mar 24, 2000 at 03:27:57PM -0800, Scott Lurndal wrote:
> > 
> > On a single bus?  Ah, alpha - 64 bit PCI bus, right?  Is it 33mhz or
> > 66 mhz?
> 
> Yup, single bus.  We are seeing this throughput on a Quadrics Elan
> interconnect.  What I am hoping to do is have my file system on one
> bus and the Elan on the other bus and hopefully saturate the link on
> the Elan with file I/O.  I'm pretty sure these PCI busses are 33MHz.
> The Elan supports 400MB/s on the wire and is capable of 66MHz so I
> would think we would be seeing better performance out of it if it were
> 66MHz.  I also think I read it was 33MHz in the owner's manual. :)

Ok. 33mhz makes sense.  That should peak at ~264 megabytes/second 
and with arbitration delays and bus turnaround delays accounted
for, about 220 MB/sec is optimal.

> > 
> > Insofar as acceptance goes, I'm trying to craft the patch in
> > such a way that it won't be objectionable to the community - 
> > but no guarantees.  We are willing to work with the community
> > to ensure acceptance eventually.   It is likely that the XFS
> > work will make use of the scsi raw stuff for performance reasons, 
> > so we may push it through that vehicle - xfs should be released
> > shortly (perhaps next month).
> > 
> 
> Haha!  Yeah, we are trying to do the same sort of thing with some of our
> changes.  Make the one that most people want to depend on something
> that isn't in the kernel already.  At least this way people will see
> how these changes are used.  If someone has a work around for us that
> is already in the kernel, it is fine since I would like to avoid
> bloat, but I seriously think that the Linux kernel is still in its
> infancy and has a ways to go for scaling up to ASCI level HPC.

Agreed.

Have a good weekend, 

 scott
> 
> 
> BAPper
> 


<Prev in Thread] Current Thread [Next in Thread>