[Beowulf] Re: "hobbyists"

Mark Hahn hahn at mcmaster.ca
Tue Jun 24 15:20:35 PDT 2008


>> More specifically for HPC, linux seems designed for the desktop, and
>> for small memory machines.

the only justice I can see in that is that there hasn't been all that 
much effort to get bigpages widely/easily used.  in particular, I don't
see that scheduler or general memory-management issues in linux are
particularly biased for desktop or against HPC.

> 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).

Con didn't play the game right - you have to have the right combination of 
social engineering (especially timing and proactive response) and good tech
kungfoo.  kernel people are biased towards a certain aesthetic that doesn't
punish big-picture redesigns from scratch, but _does_ punish solutions 
in search of a problem.

so the question is, if you had a magic wand, what would you change in 
the kernel (or perhaps libc or other support libs, etc)?  most of the 
things I can think of are not clear-cut.  I'd like to be able to give 
better info from perf counters to our users (but I don't think Linux is 
really in the way).  I suspect we lose some performance due to jitter
injected by the OS (and/or our own monitoring) and would like to improve,
but again, it's hard to blame Linux.  I'd love to have better options for 
cluster-aware filesystems.  kernel-assisted network shared memory?



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