Date: Thu, 07 Jun 2012 13:12:48 +0300 From: Daniel Kalchev <daniel@digsys.bg> To: freebsd-stable@freebsd.org Subject: Re: ULE Scheduler Message-ID: <4FD07EA0.8020401@digsys.bg> In-Reply-To: <86ehprtu48.wl%momchil@xaxo.eu> References: <86fwa8szos.wl%momchil@xaxo.eu> <12782903.WNKlBIO9Im@x220.ovitrap.com> <86ehprtu48.wl%momchil@xaxo.eu>
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On 07.06.12 11:16, Momchil Ivanov wrote: > Though, it was strange seeing both processes hopping around... I will > probably go back to the 4BSD scheduler if my laptop does another > self-shutdown in the next few days as Doug suggested. You never run just two processes on FreeBSD, ever. The kernel too runs multiple threads. However small the CPU usage of the other processes is, they must run from time to time, kicking out at least one of your CPU intensive processes, possibly kicking them out both, as well. When that happens, and they are queued to run again it does not matter much on which core they ran before, because chances are it's cache will be invalidated anyway. Also, different CPUs have different cache affinity. ULE is supposed to be aware of this, while the 4BSD scheduler is not. In any case, on an older single/dual core CPU there is rarely any difference between both schedulers. Differences might appear in modern multi-core CPUs.. Daniel
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