[RFT][patch] Scheduling for HTT and not only

[Mike Meyer]

On Tue, 10 Apr 2012 12:58:00 -0400
Arnaud Lacombe <lacombar at gmail.com> wrote:
> Let me disagree on your conclusion. If OS A does a task in X seconds,
> and OS B does the same task in Y seconds, if Y > X, then OS B is just
> not performing good enough.

Others have pointed out one problem with this statement. Let me point
out another:

It ignores the purpose of the system. If you change the task to doing
N concurrent versions of the task, and OS A time increases linearly
with the number of tasks (say it's time X*N) but OS B stair-steps at
the number of processors in the system (i.e. Y*floor(N/P)), then OS A
is just not performing good enough.

A more concrete example: if OS B spends a couple of microseconds
optimizing disk access order and OS A doesn't, then a single process
writing to disk on OS A could well run faster than the same on OS
B. However, the maximum throughput on OS B as you add process will be
higher than it is on OS A. Which one you want will depend on what
you're using the system for.

       <mike
-- 
Mike Meyer <mwm at mired.org>		http://www.mired.org/
Independent Software developer/SCM consultant, email for more information.

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