Re: [announce] [patch] Voluntary Kernel Preemption Patch

Andrea Arcangeli
2004-07-10T15:58:49Z

On Sat, Jul 10, 2004 at 02:48:14PM +0200, Ingo Molnar wrote:
> if you dont care about latencies and want to maximize throughput (for
> e.g. servers) then you dont want to enable CONFIG_PREEMPT_VOLUNTARY.
> That way you get artificial batching of parallel workloads.

you just agreed a second time to make all the pollution go away, so why
are you talking about servers now? I mean, I don't see why production
environments should run the benchmarking testcode. And I totally
disagree CONFIG_PREEMPT_VOLUNTARY disabled could provide any benefit on
a server (even with the benchmarking on). Servers have to start the next
I/O too to avoid leaving some disk idle during a copy-user etc..

let's assume you convert the benchmark sysctl knob into a
CONFIG_LOW_RESCHEDULE_OVERHEAD as I suggested in the 30 lines rant, only
then it could make sense to classify some of the scheduling points as
"high-overhead", but I don't see the need of
CONFIG_LOW_RESCHEDULE_OVERHEAD happening any time soon. Though such a
config option would make sense theoretically.