Date: Thu, 06 Jun 2002 20:22:23 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: j mckitrick <jcm@FreeBSD-uk.eu.org> Cc: freebsd-chat@freebsd.org, "Kurt J. Lidl" <lidl@pix.net> Subject: Re: SMP/5.0 performance on single CPU? Message-ID: <XFMail.20020606202223.jhb@FreeBSD.org> In-Reply-To: <20020607010446.A79818@dogma.freebsd-uk.eu.org>
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On 07-Jun-2002 j mckitrick wrote: >| I don't know how much overhead the locking system that FreeBSD is >| using will impose on a uniprocessor machine, but I would guess >| anywhere from 10%-25% slower. I think that only 10% would be pretty >| impressive for the very first release. Again -- this is a *guess*. > > Any idea if a custom kernel can completely leave out the SMP code and > end up comparable to 4.x? A UP kernel will leave out some of the overhead, but SMPng fundamentally changes the way you protect data in the kernel against interrupt handlers as well as from other threads on other CPU's (basically we are now solving that problem in a more general case) so you can't just turn it all off. -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-chat" in the body of the message
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