Received:  by oss.sgi.com id <S42253AbQHHWmZ>;
	Tue, 8 Aug 2000 15:42:25 -0700
Received: from pneumatic-tube.sgi.com ([204.94.214.22]:35191 "EHLO
        pneumatic-tube.sgi.com") by oss.sgi.com with ESMTP
	id <S42218AbQHHWjp>; Tue, 8 Aug 2000 15:39:45 -0700
Received: from nodin.corp.sgi.com (nodin.corp.sgi.com [192.26.51.193]) by pneumatic-tube.sgi.com (980327.SGI.8.8.8-aspam/980310.SGI-aspam) via ESMTP id PAA05937
	for <linux-scalability@oss.sgi.com>; Tue, 8 Aug 2000 15:44:37 -0700 (PDT)
	mail_from (kanoj@google.engr.sgi.com)
Received: from google.engr.sgi.com ([163.154.10.145]) by nodin.corp.sgi.com (980427.SGI.8.8.8/980728.SGI.AUTOCF) via ESMTP id PAA47338 for <linux-scalability@oss.sgi.com>; Tue, 8 Aug 2000 15:38:04 -0700 (PDT)
Received: (from kanoj@localhost)
	by google.engr.sgi.com (SGI-8.9.3/8.9.3) id PAA48216;
	Tue, 8 Aug 2000 15:35:32 -0700 (PDT)
From:   Kanoj Sarcar <kanoj@google.engr.sgi.com>
Message-Id: <200008082235.PAA48216@google.engr.sgi.com>
Subject: Re: [RFC] Adding the notion of System vs. Application processors
To:     clemej@alum.rpi.edu (PianoMan)
Date:   Tue, 8 Aug 2000 15:35:32 -0700 (PDT)
Cc:     dimitris@cthulhu.engr.sgi.com (Dimitris Michailidis),
        linux-scalability@oss.sgi.com
In-Reply-To: <Pine.LNX.4.20.0008081604530.15916-100000@pianoman.cluster.toy> from "PianoMan" at Aug 08, 2000 04:37:49 PM
X-Mailer: ELM [version 2.5 PL2]
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Sender: owner-LinuxScalability@oss.sgi.com
Precedence: bulk
Return-Path: <owner-LinuxScalability@oss.sgi.com>
X-Orcpt: rfc822;linux-scalability-outgoing

> 
> except, like you said, you need the system call .... Also, I have already

As I noted to you in my first response to you, I did everything I could
to get a system call to do pinning. It is not that hard to do, and I 
have created primitive patches towards this in the past, except that it
will not go into 2.4. No SGI scret there ...

> > Don't turn off the timer interrupt.  It would mess up time accounting.  We
> > also need it for slab cache management.  IPIs must also be left on.

FWIW, on IRIX, you _can_ turn off the timer interrupt on specific cpus,
as well as IPIs, but these were a headache to get right ... probably 
worth it, just to be able to claim realtime latencies ....

> mechanism's we need to do the rest in user space.  Please realize that I
> do not work for SGI, I don't know what you've got up your sleeves... I did
> not know you were getting ready to add a syscall to do the processor
> pinning....

See above ...

Kanoj