From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: Re: Poor HVM performance with 8 vcpus Date: Wed, 07 Oct 2009 10:31:05 +0200 Message-ID: <4ACC51C9.5080408@ts.fujitsu.com> References: <4ACC3B49.4060500@ts.fujitsu.com> <4FA716B1526C7C4DB0375C6DADBC4EA342A68E5C92@LONPMAILBOX01.citrite.net> <4FA716B1526C7C4DB0375C6DADBC4EA342A68E5C95@LONPMAILBOX01.citrite.net> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4FA716B1526C7C4DB0375C6DADBC4EA342A68E5C95@LONPMAILBOX01.citrite.net> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Ian Pratt Cc: James Harper , "xen-devel@lists.xensource.com" List-Id: xen-devel@lists.xenproject.org Ian Pratt wrote: > >> Are there any other of these heuristics tucked away in xen? Would there >> be any benefit to specifying the OS being virtualised in the config? Eg >> "os=windows"? > > That's really the only one that springs to mind. > > Given how simple a predictor would be, I think that's the best approach. > > Setting the OS in the config file is a little tricky as in a couple of instances you'd want to know the exact version (linux moved the 64b direct mapped region at some point during 2.6 development). I think it is a bad idea in most cases to use such a basic parameter like "os=xyz" to tune some specific behaviour. It may be useful to set some default parameters, but there should be an explicit parameter as well, e.g. "shadow_heuristic=direct-mapped@address" Juergen -- Juergen Gross Principal Developer Operating Systems TSP ES&S SWE OS6 Telephone: +49 (0) 89 636 47950 Fujitsu Technolgy Solutions e-mail: juergen.gross@ts.fujitsu.com Otto-Hahn-Ring 6 Internet: ts.fujitsu.com D-81739 Muenchen Company details: ts.fujitsu.com/imprint.html