From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756171Ab3AROrA (ORCPT ); Fri, 18 Jan 2013 09:47:00 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:41837 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752722Ab3AROq6 (ORCPT ); Fri, 18 Jan 2013 09:46:58 -0500 Date: Fri, 18 Jan 2013 09:46:48 -0500 From: Konrad Rzeszutek Wilk To: Ian Campbell Cc: "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" , "annie.li@oracle.com" , "msw@amazon.com" Subject: Re: [Xen-devel] [PATCH] xen/grant-table: Force to use v1 of grants. Message-ID: <20130118144648.GD9214@phenom.dumpdata.com> References: <1358371369-19089-1-git-send-email-konrad.wilk@oracle.com> <1358428356.13856.55.camel@zakaz.uk.xensource.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1358428356.13856.55.camel@zakaz.uk.xensource.com> User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: ucsinet21.oracle.com [156.151.31.93] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 17, 2013 at 01:12:36PM +0000, Ian Campbell wrote: > On Wed, 2013-01-16 at 21:22 +0000, Konrad Rzeszutek Wilk wrote: > > Note: The hypervisor provides an over-ride for the default > > of 32 frames (pages) per guest: gnttab_max_nr_frames=X > > Should we consider increasing this value? The fuzzy math is that for a VIF, you end up using 512 grants. For a VBD it is 352 grants. With V1 you have 512 grants in a page, with V2 you have 256. So roughly the math is that you can at max 31VIFs and 1VBD with V1 (PVHVM guests) and 15VIFs and 1VBD with V2 (so all PV guests). I would increase the value, but I don't know what a good value is. > > Ian. >