From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1GEx1l-0006pG-4L for qemu-devel@nongnu.org; Sun, 20 Aug 2006 19:48:25 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1GEx1j-0006oS-0n for qemu-devel@nongnu.org; Sun, 20 Aug 2006 19:48:24 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1GEx1i-0006oP-CT for qemu-devel@nongnu.org; Sun, 20 Aug 2006 19:48:22 -0400 Received: from [64.233.162.201] (helo=nz-out-0102.google.com) by monty-python.gnu.org with esmtp (Exim 4.52) id 1GEx8y-0003Kl-Jg for qemu-devel@nongnu.org; Sun, 20 Aug 2006 19:55:52 -0400 Received: by nz-out-0102.google.com with SMTP id x7so696195nzc for ; Sun, 20 Aug 2006 16:48:21 -0700 (PDT) Date: Mon, 21 Aug 2006 02:48:20 +0300 From: Paul Sokolovsky Message-ID: <576442285.20060821024820@gmail.com> Subject: Re[2]: [Qemu-devel] qemu dynamic translation (system design) question In-Reply-To: <3ed52ec0608200823y6e803330q8ece342dde16945e@mail.gmail.com> References: <5226555.1155980264507.JavaMail.www@wwinf1629> <3ed52ec0608200823y6e803330q8ece342dde16945e@mail.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Reply-To: Paul Sokolovsky , qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "S.P.T.Krishnan" Cc: qemu-devel@nongnu.org Hello S.P.T.Krishnan, Sunday, August 20, 2006, 6:23:11 PM, you wrote: > Hi Laurent, > Thanks for the direction. > I am just thinking. If I run a guest OS once and observe the blocks > that are translated and may be reused. Then I again re-run the OS, > can I expect the same blocks are translated ? i.e., is qemu > consistent on how it partitions the asm into blocks on successive runs > or the guest OS ? > Note: in both cases the user doesn't interact with the Guest OS. It > is up for, say 1 min and then shutdown in both runs. My 2 cents of pure scholastic reasoning: Let's assume that QEMU uses deterministic rules for block translation. Then, it just translates what CPU goes thru. Does any contemporary OS leads CPU in deterministic ways? No. It largely depends on various environment parameters, of which user interaction is not the last. There're interrupts occuring in rather random places with respect to mainline execution, I/O delays, etc. As these parameters in guest OS depend on QEMU's interaction with host OS, they are not deterministic in it either. Well, but does QEMU's translation itself deterministic? Not really, as it uses caches, and thus depend on memory parameters in host OS. > regards, > Krishnan -- Best regards, Paul mailto:pmiscml@gmail.com