Date: Thu, 11 Aug 2005 09:13:10 -0400 From: John Baldwin <jhb@FreeBSD.org> To: freebsd-arch@freebsd.org Cc: gnn@freebsd.org Subject: Re: Special schedulers, one CPU only kernel, one only userland Message-ID: <200508110913.11867.jhb@FreeBSD.org> In-Reply-To: <m2d5oldy12.wl%gnn@neville-neil.com> References: <42F9ECF2.8080809@freebsd.org> <20050810.162006.48492066.imp@bsdimp.com> <m2d5oldy12.wl%gnn@neville-neil.com>
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On Wednesday 10 August 2005 10:10 pm, gnn@freebsd.org wrote: > But, the question, which is interesting to me for other reasons > (namely putting in various real-time schedulers) was not answered. Do > we currently have the requisite primitives to implement different > schedulers or is there still a lot of jiggery/pokery required? Yes, there is some room for different schedulers, but the idea of using a master/slave SMP system is not ust a different scheduler, but an entirely different SMP architecture. That said, if you added one more sched_foo call for synchronous kernel entry in trap() and syscall(), you probably could provide a master/slave setup via a custom scheduler. It would be more optimal to also tweak the low-level routing of interrupts to CPUs on architectures that support it as well, though that would not be required. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org
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