From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <18408.59112.945786.488350@cargo.ozlabs.ibm.com> Date: Tue, 25 Mar 2008 22:50:00 +1100 From: Paul Mackerras Subject: Re: larger default page sizes... In-Reply-To: <20080324.211532.33163290.davem@davemloft.net> References: <20080324.133722.38645342.davem@davemloft.net> <18408.29107.709577.374424@cargo.ozlabs.ibm.com> <20080324.211532.33163290.davem@davemloft.net> Sender: owner-linux-mm@kvack.org Return-Path: To: David Miller Cc: clameter@sgi.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-ia64@vger.kernel.org, torvalds@linux-foundation.org List-ID: David Miller writes: > From: Paul Mackerras > Date: Tue, 25 Mar 2008 14:29:55 +1100 > > > The performance advantage of using hardware 64k pages is pretty > > compelling, on a wide range of programs, and particularly on HPC apps. > > Please read the rest of my responses in this thread, you > can have your HPC cake and eat it too. It's not just HPC, as I pointed out, it's pretty much everything, including kernel compiles. And "use hugepages" is a pretty inadequate answer given the restrictions of hugepages and the difficulty of using them. How do I get gcc to use hugepages, for instance? Using 64k pages gives us a performance boost for almost everything without the user having to do anything. If the hugepage stuff was in a state where it enabled large pages to be used for mapping an existing program, where possible, without any changes to the executable, then I would agree with you. But it isn't, it's a long way from that, and (as I understand it) Linus has in the past opposed the suggestion that we should move in that direction. Paul. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org