From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: Re: KVM got slow after adding more physical memory to host - SOLVED Date: Thu, 08 Sep 2011 18:58:19 +0400 Message-ID: <4E68D80B.5060609@msgid.tls.msk.ru> References: <20110906140201.GF18218@pcnci.linuxbox.cz> <4E663897.60901@redhat.com> <20110906153801.GA2152@nik-comp.lan> <4E664036.20308@redhat.com> <20110906160113.GB2152@nik-comp.lan> <4E66450A.8070302@redhat.com> <20110906161045.GL26451@redhat.com> <20110906163029.GC2152@nik-comp.lan> <4E6651FB.3050208@redhat.com> <20110906192235.GA2293@nik-comp.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Avi Kivity , Gleb Natapov , kvm@vger.kernel.org, pavel.miklik@linuxbox.cz, lukas.deseyve@linuxbox.cz To: Nikola Ciprich Return-path: Received: from isrv.corpit.ru ([86.62.121.231]:49020 "EHLO isrv.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751795Ab1IHO6X (ORCPT ); Thu, 8 Sep 2011 10:58:23 -0400 In-Reply-To: <20110906192235.GA2293@nik-comp.lan> Sender: kvm-owner@vger.kernel.org List-ID: On 06.09.2011 23:22, Nikola Ciprich wrote: > Hello guys, > > thanks to both of You for Your replies. The problem is solved, > exactly as Avi said, the DMA in windows got somehow disabled. > So this certainly was not related to adding the memory... > > anyways, note for further generations: > in windows XP, the DMA usage can be checked in > Device Manager->IDE ATA/ATAPI Controllers -> Properties->Advanced Settings > Current Transfer Mode must be Multi-Word DMA2 or something similar, > NOT PIO! > > The way I enabled this, was to uninstall both primary and secondary controller > in device controller, then also uninstall Intel controller, and THEN rebooting (NOT sooner!) > after reboot, controllers got detected and installed again, with DMA properly enabled. > Note that when controller is in PIO mode, this is really a patience test, switching to DMA took > me like half an hour to complete, so slow the system was :-/ You can open regedit and search for "NoIDE" - it should find one key with that name, with value "1" or "yes" - just delete it, there's no need to go that route with removing/reinstalling device drivers. The reason why it has been disabled is - most likely - due to some timeout while handling i/o -- eg, when your host was loaded too much or were swapping - you should be able to find something about that in windows event log. /mjt