From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Class: urn:content-classes:message MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT Subject: RE: Regression with SLUB on Netperf and Volanomark Date: Thu, 3 May 2007 16:28:12 -0700 Message-ID: <9D2C22909C6E774EBFB8B5583AE5291C02786032@fmsmsx414.amr.corp.intel.com> In-Reply-To: From: "Chen, Tim C" Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter , Tim Chen Cc: "Siddha, Suresh B" , "Zhang, Yanmin" , "Wang, Peter Xihong" , Arjan van de Ven , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: Christoph Lameter wrote: > Try to boot with > > slub_max_order=4 slub_min_objects=8 > > If that does not help increase slub_min_objects to 16. > We are still seeing a 5% regression on TCP streaming with slub_min_objects set at 16 and a 10% regression for Volanomark, after increasing slub_min_objects to 16 and setting slub_max_order=4 and using the 2.6.21-rc7-mm2 kernel. The performance between slub_min_objects=8 and 16 are similar. >> We found that for Netperf's TCP streaming tests in a loop back mode, >> the TCP streaming performance is about 7% worse when SLUB is enabled >> on >> 2.6.21-rc7-mm1 kernel (x86_64). This test have a lot of sk_buff >> allocation/deallocation. > > 2.6.21-rc7-mm2 contains some performance fixes that may or may not be > useful to you. We've switched to 2.6.21-rc7-mm2 in our tests now. >> >> For Volanomark, the performance is 7% worse for Woodcrest and 12% >> worse for Clovertown. > > SLUBs "queueing" is restricted to the number of objects that fit in > page order slab. SLAB can queue more objects since it has true queues. > Increasing the page size that SLUB uses may fix the problem but then > we run into higher page order issues. > > Check slabinfo output for the network slabs and see what order is > used. The number of objects per slab is important for performance. The order used is 0 for the buffer_head, which is the most used object. I think they are 104 bytes per object. Tim -- 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