Date: Wed, 27 Aug 1997 08:21:50 -0500 (CDT) From: Kyle Mestery <mestery@winternet.com> To: Peter Stubbs <peters@gil.com.au> Cc: smp@FreeBSD.ORG Subject: Re: A how does it work question. Message-ID: <Pine.GSO.3.96.970827080051.7005C-100000@tundra.winternet.com> In-Reply-To: <199708271236.WAA17211@iccu6.ipswich.gil.com.au>
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On Wed, 27 Aug 1997, Peter Stubbs wrote: > I've been forced to sell my soul lately by doing a couple of MS Win > NT courses ( mouths to feed etc.. ). It seems that NT runs a > seperate instance of the kernel on each CPU present to provide it's > SMP support. > > Is this the way FBSD smp does it? As far as I know, no. There is only one copy of the kernel running. At present, access to the kernel is only allowed for one CPU (except for a few areas), Steve has been working on making it reentrant. > Is this the only way to do it? No. Having the kernel be reentrant is another way. This requires the correct lock "pushdown" into the kernel. Instead of one giant lock, subsystems can each have their own lock, allowing multiple processors to be in different sections of the kernel. This allows for increased parallelism. > Doesn't this mean that lots more memory would be used keeping data > for 2 kernels? > I would assume so, but I dont know for sure. Kyle Mestery StorageTek's Network Systems Group 7600 Boone Ave. N., Brooklyn Park, MN 55428 mesteka@anubis.network.com, mestery@winternet.com
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