From: jbarnes@sgi.com (Jesse Barnes)
To: "Martin J. Bligh" <mbligh@aracnet.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Memory mapped IO vs Port IO
Date: Fri, 12 Sep 2003 12:51:52 -0700 [thread overview]
Message-ID: <20030912195152.GA1353@sgi.com> (raw)
In-Reply-To: <223220000.1063393087@flay>
On Fri, Sep 12, 2003 at 11:58:07AM -0700, Martin J. Bligh wrote:
> >> Also - a perhaps more useful test is a write followed by a read.
> >
> > Well, someone else will have to run that test. On Altix, a read() is
> > freakishly expensive, and I'm not really interested in showing everyone
> > how bad it is ;)
>
> I find percentile comparisons useful for hiding the embarassement
> of occasional hardware realities ;-) (ie what's the speed *ratio*
> between the two types of read).
Well, in our case, read() and in() will be pretty close,
percentage-wise. The read() in itself is so bad that I think the
additional badness of in() will be mostly hidden.
Jesse
next prev parent reply other threads:[~2003-09-12 19:51 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20030911192550.7dfaf08c.ak@suse.de.suse.lists.linux.kernel>
[not found] ` <1063308053.4430.37.camel@huykhoi.suse.lists.linux.kernel>
[not found] ` <20030912162713.GA4852@sgi.com.suse.lists.linux.kernel>
[not found] ` <20030912174807.GA629@sgi.com.suse.lists.linux.kernel>
2003-09-12 18:00 ` Memory mapped IO vs Port IO Andi Kleen
2003-09-12 18:04 ` Jesse Barnes
2003-09-12 18:09 ` Andi Kleen
2003-09-12 18:11 ` Tim Hockin
2003-09-12 18:24 ` Jesse Barnes
2003-09-12 18:29 ` Andi Kleen
2003-09-12 18:58 ` Martin J. Bligh
2003-09-12 19:51 ` Jesse Barnes [this message]
2003-09-12 16:41 John Bradford
2003-09-12 21:52 ` Mike Fedyk
2003-09-13 4:01 ` Mike Fedyk
[not found] <20030911160116.GI21596@parcelfarce.linux.theplanet.co.uk.suse.lists.linux.kernel>
2003-09-11 16:17 ` Andi Kleen
2003-09-11 16:25 ` Matthew Wilcox
2003-09-11 16:31 ` Andi Kleen
2003-09-11 16:42 ` Matthew Wilcox
2003-09-11 17:12 ` Jamie Lokier
2003-09-11 17:25 ` Andi Kleen
2003-09-12 1:39 ` jw schultz
2003-09-12 16:10 ` Anthony Dominic Truong
2003-09-12 16:22 ` Jamie Lokier
2003-09-12 16:27 ` Jesse Barnes
2003-09-12 17:48 ` Jesse Barnes
2003-09-11 17:13 ` Jamie Lokier
[not found] ` <20030911161450.GA23536@sgi.com.suse.lists.linux.kernel>
2003-09-11 16:20 ` Andi Kleen
-- strict thread matches above, loose matches on Subject: below --
2003-09-11 16:01 Matthew Wilcox
2003-09-11 16:14 ` Måns Rullgård
2003-09-11 16:14 ` Jesse Barnes
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