Date: Wed, 27 Aug 1997 07:27:49 -0700 From: David Greenman <dg@root.com> To: Christopher Petrilli <petrilli@amber.org> Cc: Kyle Mestery <mestery@winternet.com>, Peter Stubbs <peters@gil.com.au>, smp@FreeBSD.ORG Subject: Re: A how does it work question. Message-ID: <199708271427.HAA01182@implode.root.com> In-Reply-To: Your message of "Wed, 27 Aug 1997 10:16:41 EDT." <Pine.BSF.3.95q.970827101440.20292B-100000@chaos.amber.org>
next in thread | previous in thread | raw e-mail | index | archive | help
>In the end, I would think that software would be the conjstriction point >(in fact seperate memory makes it an MPP system, not an AMP/SMP system). >This is the concept behind ccNUMA, etc... > >Because of the nature of the FreeBSD kernel (and I suppose the probably >applies to Linux, but don't know), all I/O is threaded thru the #0 CPU, >and thereby it becomes a HUGE bottleneck. > >Am I correct? No, you are not correct. In FreeBSD, either CPU may service I/O requests. ...they just can't do it simultaneously. This does not mean that FreeBSD is ASMP. Steve is working on some stuff right now that will allow multiple CPUs to simultaneously process interrupts which should help to scale the system better on multiple CPUs, but in any case, this has nothing to do with SMP vs. ASMP. > This was what I was taught was the definition of a AMP >system, was that a single CPU controlled all I/O on the system, which is >why you have to go SMP to scale to X, and MPP to keep going from there. Yes, but that's not what FreeBSD does. -DG David Greenman Core-team/Principal Architect, The FreeBSD Project
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?199708271427.HAA01182>