From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <6177643.1173082156861.JavaMail.ngmail@domain.hid> Date: Mon, 5 Mar 2007 09:09:16 +0100 (CET) From: "M. Koehrer" MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: [Xenomai-help] Dual Core CPU - L2 Cache organization/reservation List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: xenomai@xenomai.org Hi all, I made excellent results with Xenomai and the dual core Pentium D CPU. I use one of the cores for real time code, the other core is used for house= keeping, communication... Excellent means, that the runtime jitter of the real time application is ex= tremely low. For example, I have a physical model running that takes about 40 microsecon= ds to run. The runtime jitter on the dual core CPU is less than 3 microseconds. On the= uni processor machine, the runtime jitter is about 40-60 (!) microseconds. On the dual core CPU the model seems to run completely out of the cache whi= ch is perfect for achieving excellent computation times. On the UP system, the non-real time code seems= to "eat up" the cache occasionally used by the real time core, i.e. the re= al time code has to re-load its cache from memory. Now I read about the way the cache is organized in Intel's Core 2 Duo serie= s. Here one common cache is=20 used that is shared between both cores. I have now the fear, that the Core 2 Duo CPU does not show this excellent r= esults as the Pentium D as the non-real time code might "eat up" the cache = as it does on a UP system. Or is there a way that allows me to "reserve" parts of the common cache for= one Core (or for the real time application, i.e. for certain physical addr= esses)? Of course a real Multi CPU system (Xeon based) might help (Server/Workstati= on), however these systems=20 are fairly expensive compared to the Core 2 Duo desktop systems... Thanks for all feedback on this issue! Regards Mathias --=20 Mathias Koehrer mathias_koehrer@domain.hid Viel oder wenig? Schnell oder langsam? Unbegrenzt surfen + telefonieren ohne Zeit- und Volumenbegrenzung? DAS TOP ANGEBOT JETZT bei Arcor: g=FCnsti= g und schnell mit DSL - das All-Inclusive-Paket f=FCr clevere Doppel-Sparer, nur 39,85 =80 inkl. DSL- und ISDN-Grundgeb=FChr! http://www.arcor.de/rd/emf-dsl-2