From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Egger Subject: Re: [PATCH 1/4]X86 microcode: cancel redundant input parameter of microcode functions Date: Thu, 22 Jan 2009 12:07:49 +0100 Message-ID: <200901221207.50153.Christoph.Egger@amd.com> References: <706158FABBBA044BAD4FE898A02E4BC2223BD253@pdsmsx503.ccr.corp.intel.com> <200901220942.02201.Christoph.Egger@amd.com> <706158FABBBA044BAD4FE898A02E4BC2223BD483@pdsmsx503.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <706158FABBBA044BAD4FE898A02E4BC2223BD483@pdsmsx503.ccr.corp.intel.com> Content-Disposition: inline List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: "Liu, Jinsong" Cc: "xen-devel@lists.xensource.com" , Keir Fraser List-Id: xen-devel@lists.xenproject.org On Thursday 22 January 2009 11:54:15 Liu, Jinsong wrote: > Christoph Egger wrote: > > On Thursday 22 January 2009 04:08:21 Liu, Jinsong wrote: > >> X86 microcode: cancel redundant input parameter of microcode > >> functions > >> > >> Cancel redundant input parameter 'uci', since it can get from > >> another input parameter 'cpu' as index. > >> > >> Signed-off-by: Liu, Jinsong > > > > I added the parameter 'uci' to reduce dependency on a global variable. > > That improves reentrancy and cache locality. > > > > If you want to go a step forward rather back, then remove the 'cpu' > > parameter instead. > > > > Christoph > > I think the input parameter 'cpu' is better than 'uci' since 'cpu' is much > clear to developer with explicit meaning, so between the 2 redundant > parameters 'uci' and 'cpu', we should remove 'uci', just like what native > linux microcode functions do. What linux does, doesn't matter here. Dom0 just has to make the hypercall. This is nothing linux specific. > As for cache locality, it's not important for microcode functions since > it's not in key path, seldom be called. Right, but better reentrancy is always good. > BTW, we'd better keep consistent > with native linux code for the sake of futher porting and upgrade, you > know, the latest linux kernel (2.6.28) still has some issues for microcode > ... You should have hear yourself. Someone else can say: BTW, we'd better keep consistent with native Solaris code for the sake of further porting and upgrade. It doesn't suffer on the Linux issues. And another guy can say: BTW, we'd better keep consistent with native BSD code for the sake of further porting and upgrade. You see what I mean? Christoph -- ---to satisfy European Law for business letters: Advanced Micro Devices GmbH Karl-Hammerschmidt-Str. 34, 85609 Dornach b. Muenchen Geschaeftsfuehrer: Jochen Polster, Thomas M. McCoy, Giuliano Meroni Sitz: Dornach, Gemeinde Aschheim, Landkreis Muenchen Registergericht Muenchen, HRB Nr. 43632