[Beowulf] Re: "hobbyists"

[Lombard, David N]

On Tue, Jun 24, 2008 at 05:46:17PM +0100, Tim Cutts wrote:
> 
> On 23 Jun 2008, at 7:41 pm, Kyle Spaans wrote:
> 
> >On Fri, Jun 20, 2008 at 03:33:19PM -0400, Lawrence Stewart wrote:
> >>More specifically for HPC, linux seems designed for the desktop, and
> >>for small memory machines.
> >
> >That's funny, because I've heard people get scared that it was the  
> >complete opposite. That Linux was driven by Big Iron, and that no  
> >one cared about the "little desktop guy" (Con Kolivas is an  
> >interesting history example).
> 
> I think it depends on which bit of "Linux" you're talking about.

Doesn't it always?

> Even now, our little HPC community are probably pretty much the only  
> people who really care that much about the performance of the OS  
> kernel itself.  Oh, OK, maybe some of the embedded guys do as well,  
> given they're trying to run it on really tiny hardware.

HPC use very few system calls and make little use of those calls beyond
large-block sequential I/O and our application networks; there are few
execution threads to stress the scheduler and memory is usually very
carefully managed.

Transaction workloads--think TPCx--spend a LOT more time in the kernel
than pretty much anything HPC.  Also consider the IOPS (I/O per second) 
metrics that the transaction and non-HPC storage providers live and die
by, and that we just don't care about.

-- 
David N. Lombard, Intel, Irvine, CA
I do not speak for Intel Corporation; all comments are strictly my own.