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

[Arnaud Lacombe]

Hi,

On Tue, Apr 10, 2012 at 4:05 PM, Mike Meyer <mwm at mired.org> wrote:
> 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.
>
You are discussing implementations in both case. If the implementation
is not good enough, let's improve it, but do not discard the numbers
on false claims.

 - Arnaud