From: Timothy Miller <miller@techsource.com>
To: Edward Tandi <ed@efix.biz>
Cc: joe briggs <jbriggs@briggsmedia.com>,
Artur Jasowicz <kernel@mousebusiness.com>,
Brian Jackson <brian@brianandsara.net>,
Bart SCHELSTRAETE <Bart.SCHELSTRAETE@dhl.com>,
Kernel mailing list <linux-kernel@vger.kernel.org>
Subject: Re: AMD MP, SMP, Tyan 2466
Date: Wed, 25 Jun 2003 18:59:05 -0400 [thread overview]
Message-ID: <3EFA2939.2060005@techsource.com> (raw)
In-Reply-To: 1056567378.31260.9.camel@wires.home.biz
Edward Tandi wrote:
>
>
> Yes, for SMP mode you absolutely need to use 'registered' RAM. Normal
> PC2100 ram will work OK with one processor but quickly fails with two (I
> had the same problems). Apparently, DDR RAM uses one clock edge to
> transfer in one direction and the opposite edge to transfer back again
> so the registers do synchronisation between one processor writing to the
> same location that the other one reads from. That's how it was explained
> to me anyway.
>
DDR memory works very much like single data rate, except that data is
transferred (in whichever direction it's going) on both edges of the
clock, thus doubling the transfer rate. The memory does not switch
between reading and writing as you describe it.
I believe registering is for reliability. Data is transferred one clock
cycle later but reduces signal loading.
next prev parent reply other threads:[~2003-06-25 22:43 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-19 16:37 Crusoe's persistent translation on linux? Samphan Raruenrom
2003-06-19 18:03 ` Vojtech Pavlik
2003-06-19 19:51 ` Samphan Raruenrom
2003-06-20 0:02 ` Nuno Silva
2003-06-20 0:16 ` Linus Torvalds
2003-06-20 2:08 ` Nuno Silva
2003-06-20 9:08 ` Xavier Bestel
2003-06-20 9:33 ` Nick Piggin
2003-06-20 14:08 ` Henning P. Schmiedehausen
2003-06-20 15:38 ` Linus Torvalds
2003-06-20 16:51 ` AMD MP, SMP, Tyan 2466 kernel
2003-06-20 17:08 ` Bart SCHELSTRAETE
2003-06-20 17:09 ` Brian Jackson
2003-06-25 17:37 ` Artur Jasowicz
2003-06-25 18:51 ` joe briggs
2003-06-25 18:16 ` Mike Dresser
2003-07-21 20:52 ` Artur Jasowicz
2003-07-22 4:02 ` Jason
2003-07-23 12:19 ` paterley
2003-07-23 20:03 ` Joe Briggs
2003-06-25 19:01 ` joe briggs
2003-06-25 18:56 ` Edward Tandi
2003-06-25 22:59 ` Timothy Miller [this message]
2003-06-25 23:17 ` Edward Tandi
2003-06-25 23:26 ` Timothy Miller
2003-06-25 23:39 ` Timothy Miller
2003-06-26 0:29 ` Edward Tandi
2003-06-25 23:40 ` Edward Tandi
2003-06-26 15:12 ` Herbert Poetzl
2003-06-25 23:35 ` Joel Jaeggli
2003-06-26 12:25 ` AMD MP, SMP, Tyan 2466, REISERFS I/O error joe briggs
2003-06-26 11:55 ` Oleg Drokin
2003-06-26 13:37 ` joe briggs
2003-06-26 23:15 ` Timothy Miller
2003-06-26 23:48 ` Joel Jaeggli
2003-06-27 13:01 ` joe briggs
2003-06-20 12:05 ` Crusoe's persistent translation on linux? Samphan Raruenrom
[not found] ` <20030619221126.B3287@ucw.cz>
2003-06-23 3:58 ` Crusoe's performance " Samphan Raruenrom
2003-06-23 5:22 ` H. Peter Anvin
2003-06-23 5:40 ` Grzegorz Jaskiewicz
2003-06-23 8:10 ` Vojtech Pavlik
2003-06-23 8:26 ` Vojtech Pavlik
2003-06-23 18:58 ` Samphan Raruenrom
2003-06-24 1:43 ` dean gaudet
2003-06-24 4:33 ` dean gaudet
2003-06-24 22:54 ` Samphan Raruenrom
2003-06-24 23:06 ` dean gaudet
2003-06-23 23:46 ` H. Peter Anvin
2003-06-24 0:51 ` H. Peter Anvin
2003-06-26 3:39 ` H. Peter Anvin
2003-06-26 4:22 ` H. Peter Anvin
[not found] ` <200306240051.RAA12097@cesium.transmeta.com>
2003-06-26 19:09 ` Samphan Raruenrom
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=3EFA2939.2060005@techsource.com \
--to=miller@techsource.com \
--cc=Bart.SCHELSTRAETE@dhl.com \
--cc=brian@brianandsara.net \
--cc=ed@efix.biz \
--cc=jbriggs@briggsmedia.com \
--cc=kernel@mousebusiness.com \
--cc=linux-kernel@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox