From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Very high memory usage with KVM Date: Sun, 09 Aug 2009 12:12:43 +0300 Message-ID: <4A7E930B.6030803@redhat.com> References: <20090725174340.GA21733@defiant.freesoftware.org> <4A6C3EAD.9040303@redhat.com> <20090726145603.GD31411@defiant.freesoftware.org> <4A6C721F.8030702@redhat.com> <20090726155012.GE31411@defiant.freesoftware.org> <4A6C821B.5020007@redhat.com> <20090808005428.GB6072@defiant.freesoftware.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit To: dbareiro@gmx.net, KVM General Return-path: Received: from mx2.redhat.com ([66.187.237.31]:58092 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753290AbZHIJGw (ORCPT ); Sun, 9 Aug 2009 05:06:52 -0400 In-Reply-To: <20090808005428.GB6072@defiant.freesoftware.org> Sender: kvm-owner@vger.kernel.org List-ID: On 08/08/2009 03:54 AM, Daniel Bareiro wrote: >> My guess is that it is due to poor swapping with pre-2.6.27 hosts. >> 15 GB used out of 16GB total is just 6% reserve, which may be a bit >> too low. With a 2.6.27 host some small amount of memory would be >> swapped out, before that you'd see thrashing. Another way to check >> is to drop one guest (or reduce total memory needed by 1GB) and see >> if you get the same results or if things improve. >> > > I was testing in another equipment of similar characteristics with 4 VMs of > 3.5 GiB of RAM on LVM and rather less the 16 GB of RAM in use in the host > machine and 4 GIB available of the 8 GIB of swap, and after to update to > KVM-88 the use of virtual memory improved enough. > > At the moment these are the statistics of memory usage: > > root@ss03:~# free > total used free shared buffers cached > Mem: 16463396 6700900 9762496 0 2805756 391884 > -/+ buffers/cache: 3503260 12960136 > Swap: 8319948 0 8319948 > > > Still I didn't update the kernel, so I am using KVM-88 with kernel > 2.6.24-19. I would like to know if this can have some disadvantage, since > in the official site of the project I was reading that kernel has to be > 2.6.25 or newer to run the kvm 76 userspace (or any newer release). > I think it's just luck; with kernel < 2.6.27 swapping behaviour will not be very good. > The reason by which I didn't update kernel is because I was with some > problems with the network interface on the host machine. Perhaps this > problem is off-topic, but if somebody can help me with this, then it would > contribute whereupon it can improve the KVM performance. > > Please take it to netdev, perhaps they can help you with this. -- error compiling committee.c: too many arguments to function