Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262392AbVEMOxl (ORCPT ); Fri, 13 May 2005 10:53:41 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262395AbVEMOxl (ORCPT ); Fri, 13 May 2005 10:53:41 -0400 Received: from relay1.tiscali.de ([62.26.116.129]:663 "EHLO webmail.tiscali.de") by vger.kernel.org with ESMTP id S262392AbVEMOxf (ORCPT ); Fri, 13 May 2005 10:53:35 -0400 Message-ID: <4284BF3C.4030501@tiscali.de> Date: Fri, 13 May 2005 16:52:44 +0200 From: Matthias-Christian Ott User-Agent: Mozilla Thunderbird 1.0 (X11/20050108) X-Accept-Language: en-us, en MIME-Version: 1.0 To: "Tetsuji \"Maverick\" Rai" CC: Chris Friesen , linux-os@analogic.com, linux-kernel@vger.kernel.org Subject: Re: Need kernel patch to compile with Intel compiler References: <377362e105051207461ff85b87@mail.gmail.com> <42837C2E.9000506@nortel.com> <377362e105051306506e3870a6@mail.gmail.com> In-Reply-To: <377362e105051306506e3870a6@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2008 Lines: 50 Tetsuji "Maverick" Rai wrote: > On 5/13/05, Chris Friesen wrote: > >>Richard B. Johnson wrote: >> >> >>>The kernel is designed to be compiled with the GNU 'C' compler >>>supplied with every distribution. It uses a lot of __asm__() >>>statements and other GNU-specific constructions. >> >>Yep. And Intel added a bunch of them to their compiler so that they >>could build a kernel with it. >> >> >>>Why would you even attempt to convert the kernel sources to >>>be compiled with some other tools? >> >>The Intel compiler is quite good at optimizing for their processors (and >>ironically for AMD ones as well). However, I think that a lot of the >>gains come from the vectorizer, which of course can't be used with >>kernel code. >> >>Chris >> > > > Yes, that's why I wanted to use Intel's compiler for kernel (of course > I didn't mean to use C++; the product's name is C++, it doesn't sell C > alone.) Its vectorization is so nice that SETI@home calculates > 20-30% faster than the original one compiled with gcc. > > But I thought it's not such a good idea to build kernel with Intel > compiler, because kernel's speed doesn't affect so much in my case. > And that vectorization isn't so effective in kernel. PGO (profile > guided optimization) is the only effective optimization in the kernel > according to > http://softwareforums.intel.com/ids/board/message?board.id=16&message.id=1504 > > So I decided not to try this...looks like too much effort and little > gain. and I guess that's why nobody is trying this now. > Yeah that's what the 2.6.5 patch does. Some People talked about 20% more speed with this patch last year. If anyone is able to patch the current kernel the patch should be in -mm. Matthias-Christian Ott - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/