SCHEDULE and high load situations

Martin Blapp mb at
Wed Aug 11 09:20:28 PDT 2004


> I've found that for throughput oriented workloads, 4BSD substantially
> outperforms ULE, but I haven't tried it with Jeff's latest set of patches
> (committed a day or two ago).  You don't mention if your box is SMP, btw
> -- I've noticed some load balancing problems with ULE previously, but
> haven't checked if they were resolved.  Anecdotal opinion seems generally
> to be that interactivity is observably better with ULE than 4BSD, but that
> 4BSD appears to do a better job under load.

If the load doesn't grow over 2, I'd say the scheduler is broken. This is SMP

> SMP.  Some of the wins on SMP have been from moving to adaptive mutexes by
> default (most recently, for Giant on i386); others from improved fine
> grain locking in VM and networking, and general optimization of
> synchronization primitives, scheduling, wakeups/locking, etc.

The tests I've done are with your adaptive giant option and Jeff's ULE patches.


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