From mboxrd@z Thu Jan 1 00:00:00 1970 Message-Id: <3.0.6.32.20030104233111.007ed3c0@boo.net> Date: Sat, 04 Jan 2003 23:31:11 -0500 From: Jason Papadopoulos Subject: [PATCH] rewritten page coloring for 2.4.20 kernel Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Sender: owner-linux-mm@kvack.org Return-Path: To: linux-mm@kvack.org Cc: linux-kernel@vger.kernel.org List-ID: Hello. After a year in stasis, I've completely rebuilt my kernel patch that implements page coloring. Improvements include: - Page coloring is now hardwired into the kernel. The hash queues now use bootmem, and page coloring is always on. The patch still creates /proc/page_color for statistics, but that will go away in time. - Automatic detection of external cache size on many architectures. I have no idea if any of this code works, since I don't have any of the target machines. The preferred way to initialize the coloring is by passing "page_color=" as a boot argument. - NUMA-safe, discontig-safe Right now the actual page coloring algorithm is the same as in previous patches, and performs the same. In the next few weeks I'll be trying new ideas that will hopefully reduce fragmentation and increase performance. This is an early attempt to get some feedback on mistakes I may have made. lmbench shows no real gains or losses compared to an unpatched kernel; some of the page fault and protection fault times are slightly slower, but it's close to the rounding error over five lmbench runs. Here are all the performance results I have for the patch: 1. Compile of 2.4.20 kernel with gcc 3.1.1 on 466MHz DS10 Alphaserver with 2MB cache: repeatable 1% speedup (573 sec vs. 579 sec) 2. 1000x1000 matrix multiply: 10% speedup on Athlon II with 512kB cache (Dieter Nutzel) 3. Without page coloring, the alpha gets 80% of max theoretical bandwidth for working sets at most 1/8 the size of its L2 cache. For larger working sets than that the achieved bandwidth is only 30%-50% of max. With page coloring, the 80% figure applies to the entire L2 cache. 4. FFTW (alpha): 30% speedup for 64k-point FFTs, 20% speedup for 1M-point FFTs Patch is available at www.boo.net/~jasonp/page_color-2.4.20-20030104.patch Thanks in advance for any feedback. jasonp -- 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/