Messages in this thread | | | From | "Protasevich, Natalie" <> | Subject | RE: [PATCH 2/2][2.5]Unisys ES7000 platform subarch | Date | Wed, 11 Jun 2003 11:40:05 -0500 |
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Mika, I always get this cluster terminology questions :) I have to remove these words once and for all (I thought I did... I will though.)
Clustering on ES7000 follows Intel guidelines, but not quite fall into certain cluster model category. According to Intel book, cluster can be flat (on the same bus) or hierarchical (physically separate bus segments). Flat cluster uses serial bus messaging (like on xAPIC systems) and can support 15 agents. On both APIC models that ES7000 utilizes, it can support 32 processors (with xAPICs, 64 hypothreaded P4's, if only OS could support that). It has special arrangement for the APIC buses and corresponding numbering for APICs, which reflects its topological nature, so the conventional APIC cluster numbering schema won't work. Due to those differences, our clusters are not that "flat", and we call it "physical", and "logical" really means "hierarchical". I think, our cluster model names came from some previous distributions that implemented both models, I swear I didn't invent it myself. They just worked for our case.
--Natalie
-----Original Message----- From: Mika Penttilä [mailto:mika.penttila@kolumbus.fi] Sent: Wednesday, June 11, 2003 9:57 AM To: Protasevich, Natalie Cc: Linux Kernel Subject: Re: [PATCH 2/2][2.5]Unisys ES7000 platform subarch
Just out of curiosity, what are "Physical Cluster" and "Logical Cluster"? This terminology doesn't appear in Intel documentation. AFAIK, IPIs are currently always sent using logical destination mode, and in your patch ioapic entries have logical mode in cluster case. So where does physical cluster come into play?
--Mika
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