[Haskell-cafe] Google Summer of Code: a NUMA wishlist!
Sajith T S
sajith at gmail.com
Mon Mar 26 04:49:53 CEST 2012
It's last minute-ish to bring this up (in my part of the world it's
still March 25), but graduate students are famously a busy and lazy
lot. :) I study at Indiana University Bloomington, and I wish to
propose^W rush in this proposal and solicit feedback, mentors, etc
while I can.
Since student application deadline is April 6, I figure we can beat
this into a real proposal's shape by then. This probably also falls
on the naive and ambitious side of things, and I might not even know
what I'm talking about, but let's see! That's the idea of proposal,
Broadly, idea is to improve support for NUMA systems. Specifically:
-- Real physical processor affinity with forkOn . Can we fire all
CPUs if we want to? (Currently, the number passed to forkOn is
interpreted as number modulo the value returned by
-- Also kind of associated with the above: when launching processes,
we might want to specify a list of CPUs rather than the number of
CPUs. Say, a -N [0,1,3] flag rather than -N 3 flag. This shall
enable us to gawk at real pretty htop  output.
-- From a very recent discussion on parallel-haskell , we learn
that RTS' NUMA support could be improved. The hypothesis is that
allocating nurseries per Capability might be a better plan than
using global pool. We might borrow/steal ideas from hwloc  for
-- Finally, a logging/monitoring infrastructure to verify assumptions
and determine if/how local work stays.
(I would like to acknowledge my fellow conspirators and leave them
unnamed, lest they shall be embarrassed by my... naivete.)
"the lyf so short, the craft so long to lerne."
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