ULE patch, call for testers

Jeff Roberson jroberson at jroberson.net
Fri Nov 2 21:00:56 UTC 2012

On Fri, 2 Nov 2012, Eitan Adler wrote:

> On 2 November 2012 14:26, Jeff Roberson <jroberson at jroberson.net> wrote:
>> I have a small patch to the ULE scheduler that makes a fairly large change
>> to the way timeshare threads are handled.
>> http://people.freebsd.org/~jeff/schedslice.diff
>> Previously ULE used a fixed slice size for all timeshare threads.  Now it
>> scales the slice size down based on load.  This should reduce latency for
>> timeshare threads as load increases.  It is important to note that this does
>> not impact interactive threads.  But when a thread transitions to
>> interactive from timeshare it should see some improvement.  This happens
>> when something like Xorg chews up a lot of CPU.
>> If anyone has perf tests they'd like to run please report back.  I have done
>> a handful of validation.
> does it make sense to make these sysctls?
> +#define	SCHED_SLICE_DEFAULT_DIVISOR	10	/* 100 ms. */
> +#define	SCHED_SLICE_MIN_DIVISOR		4	/* DEFAULT/MIN = 25 ms. */

DEFAULT_DIVISOR is indirectly through the sysctls that modify the slice. 
The min divisor could be.  I will consider adding that.


> -- 
> Eitan Adler

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