From owner-freebsd-hackers  Fri Dec  4 08:59:46 1998
Return-Path: <owner-freebsd-hackers@FreeBSD.ORG>
Received: (from majordom@localhost)
          by hub.freebsd.org (8.8.8/8.8.8) id IAA23612
          for freebsd-hackers-outgoing; Fri, 4 Dec 1998 08:59:46 -0800 (PST)
          (envelope-from owner-freebsd-hackers@FreeBSD.ORG)
Received: from labinfo.iet.unipi.it (labinfo.iet.unipi.it [131.114.9.5])
          by hub.freebsd.org (8.8.8/8.8.8) with SMTP id IAA23546
          for <hackers@FreeBSD.ORG>; Fri, 4 Dec 1998 08:59:33 -0800 (PST)
          (envelope-from luigi@labinfo.iet.unipi.it)
Received: from localhost (luigi@localhost) by labinfo.iet.unipi.it (8.6.5/8.6.5) id PAA08600; Fri, 4 Dec 1998 15:50:38 +0100
From: Luigi Rizzo <luigi@labinfo.iet.unipi.it>
Message-Id: <199812041450.PAA08600@labinfo.iet.unipi.it>
Subject: Re: Nonblocking page fetching
To: toasty@home.dragondata.com (Kevin Day)
Date: Fri, 4 Dec 1998 15:50:38 +0100 (MET)
Cc: hackers@FreeBSD.ORG
In-Reply-To: <199812041639.KAA28408@home.dragondata.com> from "Kevin Day" at Dec 4, 98 10:38:59 am
X-Mailer: ELM [version 2.4 PL23]
Content-Type: text
Sender: owner-freebsd-hackers@FreeBSD.ORG
Precedence: bulk
X-Loop: FreeBSD.ORG

> > >>> One final note... Does anyone know what effect turning off the bzero on new
> > i think a lot of software will break.
> 
> Doesn't that break the golden rule of never assuming the contents of new
> memory?

rules are there because you can have exceptions or violations.

> > ok, so think this differently: bzero'ing occurs at memory speed which
> > could be around 200-400MB/s in your case, or 10-20us/page.
> 
> Without giving away too much information, we're using a unified memory
> system, bandwidth usage is of extreme importance.

ok... but again, i don't know if pages used as i/o buffer are bzeroed
before use -- that should not be strictly necessary.

	luigi

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-hackers" in the body of the message