From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Mosberger Date: Thu, 25 Sep 2003 06:57:10 +0000 Subject: Re: [Lse-tech] CPUSET Proposal Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org >>>>> On Wed, 24 Sep 2003 23:02:34 -0700, William Lee Irwin III said: Bill> On Wed, 24 Sep 2003 09:30:44 -0700, Stephen Hemminger Bill> said: Stephen> Looks good, but you aren't likely to get much acceptance or Stephen> testing if it only works on ia64. You need to make a Stephen> version for i386 as well. Bill> On Wed, Sep 24, 2003 at 10:02:35AM -0700, David Mosberger wrote: >> Is this true for >8-way machines? Bill> x86's architectural limitations are 64x for serial APIC -based machines Bill> (e.g. NUMA-Q) and 255x for xAPIC -based machines (no known extant > 32x Bill> machines, apparently some kind of non-architectural regression), where Bill> the non-power-of-two number of cpus is due to the broadcast ID reserved Bill> from an 8-bit interrupt controller ID space. A likely explanation for Bill> the current xAPIC limitations is the recommended (publicly documented) Bill> physical APIC ID enumeration scheme breaking down for > 32x. Bill> Custom interrupt controllers may exceed these limits, but I don't know Bill> of any that have actually been made use of to do so. Though it sucks Bill> and very, very badly, x86 is not limited to anything like 8x. I wasn't suggesting that x86 is limited to 8-way, I was wondering how many > 8-way x86 Linux machines are actually out there. I wasn't even being facetious---just curious. --david