From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <200009122018.WAA00786@piglet.grunz.lu> Date: Tue, 12 Sep 2000 22:18:48 +0200 (CEST) From: Michel Lanners Reply-To: mlan@cpu.lu Subject: zeroing pages in the idle task? To: linuxppc-dev@lists.linuxppc.org MIME-Version: 1.0 Content-Type: TEXT/plain; charset=us-ascii Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: Hi all, I've come across a 'forgotten' feature of the PPC kernels: namely zeroing pages 'in advance' in the idle task. It's a feature Cort implemented some time ago, but which is disabled by default. I've tried to enable it: [root@piglet ~]# echo 1 > /proc/sys/kernel/zero-paged and it seems to work OK: (this is after system boot, no apps started yet except 3 xterms) [mlan@piglet ~]$ cat /proc/cpuinfo processor : 0 cpu : 750 temperature : 0 C clock : 195MHz ^^^^^^ (by the way, this is wrong. Anybody with a fix?) revision : 2.2 bogomips : 575.08 zero pages : total 264 (1056Kb) current: 96 (384Kb) hits: 168/255 (65%) machine : Power Macintosh motherboard : AAPL,7500 MacRISC memory : 112MB pmac-generation : OldWorld So, a few questions: - is there any problem with using this feature? - if not, would it be a good idea to enable it by default? - or, would it be better to add it to rc.sysinit, leaving it to each distribution whether to enable it or not? I've not benchmarked anything (how would one do that?); but it seems to me it's a no-cost optimisation. Even if there's little advantage, since it's for free... Comments? Michel ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email mlan@cpu.lu | http://www.cpu.lu/~mlan | Learn Always. " ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/