SCHED_ULE should not be the default

Andriy Gapon avg at
Sat Dec 17 21:13:30 UTC 2011

on 17/12/2011 19:33 George Mitchell said the following:
> Summing up for the record, in my original test:
> 1. It doesn't matter whether X is running or not.
> 2. The problem is not limited to two or fewer CPUs.  (It also happens
>    for me on a six-CPU system.)
> 3. It doesn't require nCPU + 1 compute-bound processes, just nCPU.
> With nCPU compute-bound processes running, with SCHED_ULE, any other
> process that is interactive (which to me means frequently waiting for
> I/O) gets ABYSMAL performance -- over an order of magnitude worse than
> it gets with SCHED_4BSD under the same conditions.

I definitely do not see anything like this.
- with X
- with 2 CPUs
- with nCPU and/or nCPU + 1 compute-bound processes
- with SCHED_ULE obviously :-)
I do not get "abysmal" performance for I/O active tasks.

Perhaps there is something specific that you would want me to run and measure.

Andriy Gapon

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