From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ian Campbell Subject: Re: [PATCH v3] tools/libxc: Batch memory allocations for PV guests Date: Wed, 17 Jun 2015 12:40:46 +0100 Message-ID: <1434541246.13744.335.camel@citrix.com> References: <1434363127-31956-1-git-send-email-ross.lagerwall@citrix.com> <20150615160837.GG10177@zion.uk.xensource.com> <1434539643.13744.326.camel@citrix.com> <55815882.5070807@citrix.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <55815882.5070807@citrix.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Ross Lagerwall Cc: Ian Jackson , Stefano Stabellini , Wei Liu , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Wed, 2015-06-17 at 12:22 +0100, Ross Lagerwall wrote: > On 06/17/2015 12:14 PM, Ian Campbell wrote: > > On Mon, 2015-06-15 at 17:08 +0100, Wei Liu wrote: > >> On Mon, Jun 15, 2015 at 11:12:07AM +0100, Ross Lagerwall wrote: > >>> The current code for allocating memory for PV guests batches the > >>> hypercalls to allocate memory by allocating 1024*1024 extents of order 0 > >>> at a time. To make this faster, first try allocating extents of order 9 > >>> (2 MiB) before falling back to the order 0 allocating if the order 9 > >>> allocation fails. > >>> > >>> On my test machine this reduced the time to start a 128 GiB PV guest by > >>> about 60 seconds. > > > > From 61s or from 600s? > > It reduced the total time _by_ 60 seconds. I know, my question was whether 60s was a significant or insignificant fraction of the time take to start a guest. Seems like it was pretty significant. > I think it takes about 10 > seconds to start the guest now, but it is not related to the size of > guest memory. > > Regards