From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <41B837D6.2000504@yahoo.com.au> Date: Thu, 09 Dec 2004 22:32:38 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: Anticipatory prefaulting in the page fault handler V1 References: <41AEB44D.2040805@pobox.com> <20041201223441.3820fbc0.akpm@osdl.org> <41AEBAB9.3050705@pobox.com> <20041201230217.1d2071a8.akpm@osdl.org> <179540000.1101972418@[10.10.2.4]> <41AEC4D7.4060507@pobox.com> <20041202101029.7fe8b303.cliffw@osdl.org> <20041209105753.GB1131@elf.ucw.cz> In-Reply-To: <20041209105753.GB1131@elf.ucw.cz> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Pavel Machek Cc: Christoph Lameter , Jeff Garzik , torvalds@osdl.org, hugh@veritas.com, benh@kernel.crashing.org, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org List-ID: Pavel Machek wrote: > Hi! > > >>Standard Kernel on a 512 Cpu machine allocating 32GB with an increasing >>number of threads (and thus increasing parallellism of page faults): >> >> Gb Rep Threads User System Wall flt/cpu/s fault/wsec >> 32 3 1 1.416s 138.165s 139.050s 45073.831 45097.498 > > ... > >>Patched kernel: >> >>Gb Rep Threads User System Wall flt/cpu/s fault/wsec >> 32 3 1 1.098s 138.544s 139.063s 45053.657 45057.920 > > ... > >>These number are roughly equal to what can be accomplished with the >>page fault scalability patches. >> >>Kernel patches with both the page fault scalability patches and >>prefaulting: >> >> Gb Rep Threads User System Wall flt/cpu/s fault/wsec >> 32 10 1 4.103s 456.384s 460.046s 45541.992 45544.369 > > ... > >>The fault rate doubles when both patches are applied. > > ... > >>We are getting into an almost linear scalability in the high end with >>both patches and end up with a fault rate > 3 mio faults per second. > > > Well, with both patches you also slow single-threaded case more than > twice. What are the effects of this patch on UP system? fault/wsec is the important number. -- 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: aart@kvack.org