Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755885AbYCQDht (ORCPT ); Sun, 16 Mar 2008 23:37:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752838AbYCQDhl (ORCPT ); Sun, 16 Mar 2008 23:37:41 -0400 Received: from mga05.intel.com ([192.55.52.89]:39066 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752301AbYCQDhl (ORCPT ); Sun, 16 Mar 2008 23:37:41 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,510,1199692800"; d="scan'208";a="534908680" Subject: Re: hackbench regression since 2.6.25-rc From: "Zhang, Yanmin" To: Christoph Lameter Cc: Andrew Morton , Kay Sievers , Greg Kroah-Hartman , LKML , Ingo Molnar In-Reply-To: References: <1205394417.3215.85.camel@ymzhang> <20080313014808.f8d25c2a.akpm@linux-foundation.org> <1205400538.3215.148.camel@ymzhang> <1205463842.3215.188.camel@ymzhang> <1205478861.3215.279.camel@ymzhang> Content-Type: text/plain; charset=utf-8 Date: Mon, 17 Mar 2008 11:35:40 +0800 Message-Id: <1205724940.3215.339.camel@ymzhang> Mime-Version: 1.0 X-Mailer: Evolution 2.9.2 (2.9.2-2.fc7) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2984 Lines: 77 On Fri, 2008-03-14 at 17:15 -0700, Christoph Lameter wrote: > Here is a patch to just not perform refills but switch slabs instead. > Could check what effect doing so has on the statistics you see on the 16p? > > --- > mm/slub.c | 5 +---- > 1 file changed, 1 insertion(+), 4 deletions(-) > > Index: linux-2.6/mm/slub.c > =================================================================== > --- linux-2.6.orig/mm/slub.c 2008-03-14 16:49:36.000000000 -0700 > +++ linux-2.6/mm/slub.c 2008-03-14 16:50:04.000000000 -0700 > @@ -1474,10 +1474,7 @@ static void *__slab_alloc(struct kmem_ca > goto new_slab; > > slab_lock(c->page); > - if (unlikely(!node_match(c, node))) > - goto another_slab; > - > - stat(c, ALLOC_REFILL); > + goto another_slab; > > load_freelist: > object = c->page->freelist; There is no much help. In 2.6.25-rc5, REFILL means refill from c->page->freelist and another_slab. It's looks like its definition is confusing. In the case of hackbench, mostly, c->page->freelist is NULL. With #hackbench 100 process 2000, 100*20*2 (totoally 4000) processes are started. vmstat shows about 300~500 processes are at RUNNING state, so every processor runqueue has more than 20 processes running on 16p tigerton. Below is the data with kernel 2.6.25-rc5+your_patch. [ymzhang@lkp-tt01-x8664 ~]$ slabinfo kmalloc-512 Slabcache: kmalloc-512 Aliases: 1 Order : 0 Objects: 352 Sizes (bytes) Slabs Debug Memory ------------------------------------------------------------------------ Object : 512 Total : 56 Sanity Checks : Off Total: 229376 SlabObj: 512 Full : 36 Redzoning : Off Used : 180224 SlabSiz: 4096 Partial: 4 Poisoning : Off Loss : 49152 Loss : 0 CpuSlab: 16 Tracking : Off Lalig: 0 Align : 8 Objects: 8 Tracing : Off Lpadd: 0 kmalloc-512 has no kmem_cache operations kmalloc-512: Kernel object allocation ----------------------------------------------------------------------- No Data kmalloc-512: Kernel object freeing ------------------------------------------------------------------------ No Data kmalloc-512: No NUMA information available. Slab Perf Counter Alloc Free %Al %Fr -------------------------------------------------- Fastpath 55883575 6130576 69 7 Slowpath 24131134 73883818 30 92 Page Alloc 84844 84788 0 0 Add partial 270625 23860257 0 29 Remove partial 24046290 84752 30 0 RemoteObj/SlabFrozen 270825 439015 0 0 Total 80014709 80014394 Deactivate Full=23860293(98%) Empty=200(0%) ToHead=0(0%) ToTail=270625(1%) -- 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/