From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Date: Sat, 15 Apr 2006 05:32:10 +0000 Subject: Re: [PATCH 00/05] robust per_cpu allocation for modules Message-Id: <4440855A.7040203@yahoo.com.au> List-Id: References: <1145049535.1336.128.camel@localhost.localdomain> In-Reply-To: <1145049535.1336.128.camel@localhost.localdomain> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Steven Rostedt Cc: LKML , Andrew Morton , Linus Torvalds , Ingo Molnar , Thomas Gleixner , Andi Kleen , Martin Mares , bjornw@axis.com, schwidefsky@de.ibm.com, benedict.gaster@superh.com, lethal@linux-sh.org, Chris Zankel , Marc Gauthier , Joe Taylor , David Mosberger-Tang , rth@twiddle.net, spyro@f2s.com, starvik@axis.com, tony.luck@intel.com, linux-ia64@vger.kernel.org, ralf@linux-mips.org, linux-mips@linux-mips.org, grundler@parisc-linux.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, paulus@samba.org, linux390@de.ibm.com, davem@davemloft.net Steven Rostedt wrote: > would now create a variable called per_cpu_offset__myint in > the .data.percpu_offset section. This variable will point to the (if > defined in the kernel) __per_cpu_offset[] array. If this was a module > variable, it would point to the module per_cpu_offset[] array which is > created when the modules is loaded. If I'm following you correctly, this adds another dependent load to a per-CPU data access, and from memory that isn't node-affine. If so, I think people with SMP and NUMA kernels would care more about performance and scalability than the few k of memory this saves. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Sat, 15 Apr 2006 19:46:26 +0100 (BST) Received: from smtp109.mail.mud.yahoo.com ([209.191.85.219]:50358 "HELO smtp109.mail.mud.yahoo.com") by ftp.linux-mips.org with SMTP id S8133543AbWDOSqQ (ORCPT ); Sat, 15 Apr 2006 19:46:16 +0100 Received: (qmail 34515 invoked from network); 15 Apr 2006 05:32:25 -0000 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=yahoo.com.au; h=Received:Message-ID:Date:From:User-Agent:X-Accept-Language:MIME-Version:To:CC:Subject:References:In-Reply-To:Content-Type:Content-Transfer-Encoding; b=5xB/LXGcOqlmU7cxQqVDB2BvHv9bQNqBkpJzgwo6QEO6oiOKgrrzFoA9pylW7iF37saoVBaQxzzxort+U0SKu8buzkxu7DUqmGXWG7CsQ76Ua5lpcxxCOL/+OSEerqnavEXd54/3O4J3Ppw815kAWxhWltl6nXSEk02O0oN72lo= ; Received: from unknown (HELO ?192.168.0.1?) (nickpiggin@203.173.5.206 with plain) by smtp109.mail.mud.yahoo.com with SMTP; 15 Apr 2006 05:32:25 -0000 Message-ID: <4440855A.7040203@yahoo.com.au> Date: Sat, 15 Apr 2006 15:32:10 +1000 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.12) Gecko/20051007 Debian/1.7.12-1 X-Accept-Language: en MIME-Version: 1.0 To: Steven Rostedt CC: LKML , Andrew Morton , Linus Torvalds , Ingo Molnar , Thomas Gleixner , Andi Kleen , Martin Mares , bjornw@axis.com, schwidefsky@de.ibm.com, benedict.gaster@superh.com, lethal@linux-sh.org, Chris Zankel , Marc Gauthier , Joe Taylor , David Mosberger-Tang , rth@twiddle.net, spyro@f2s.com, starvik@axis.com, tony.luck@intel.com, linux-ia64@vger.kernel.org, ralf@linux-mips.org, linux-mips@linux-mips.org, grundler@parisc-linux.org, parisc-linux@parisc-linux.org, linuxppc-dev@ozlabs.org, paulus@samba.org, linux390@de.ibm.com, davem@davemloft.net Subject: Re: [PATCH 00/05] robust per_cpu allocation for modules References: <1145049535.1336.128.camel@localhost.localdomain> In-Reply-To: <1145049535.1336.128.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 11109 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: nickpiggin@yahoo.com.au Precedence: bulk X-list: linux-mips Steven Rostedt wrote: > would now create a variable called per_cpu_offset__myint in > the .data.percpu_offset section. This variable will point to the (if > defined in the kernel) __per_cpu_offset[] array. If this was a module > variable, it would point to the module per_cpu_offset[] array which is > created when the modules is loaded. If I'm following you correctly, this adds another dependent load to a per-CPU data access, and from memory that isn't node-affine. If so, I think people with SMP and NUMA kernels would care more about performance and scalability than the few k of memory this saves. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtp109.mail.mud.yahoo.com (smtp109.mail.mud.yahoo.com [209.191.85.219]) by ozlabs.org (Postfix) with SMTP id 161B867A03 for ; Sun, 16 Apr 2006 04:58:21 +1000 (EST) Message-ID: <4440855A.7040203@yahoo.com.au> Date: Sat, 15 Apr 2006 15:32:10 +1000 From: Nick Piggin MIME-Version: 1.0 To: Steven Rostedt Subject: Re: [PATCH 00/05] robust per_cpu allocation for modules References: <1145049535.1336.128.camel@localhost.localdomain> In-Reply-To: <1145049535.1336.128.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Cc: Andrew Morton , linux-mips@linux-mips.org, David Mosberger-Tang , linux-ia64@vger.kernel.org, Martin Mares , spyro@f2s.com, Joe Taylor , Andi Kleen , linuxppc-dev@ozlabs.org, paulus@samba.org, benedict.gaster@superh.com, bjornw@axis.com, Ingo Molnar , grundler@parisc-linux.org, starvik@axis.com, Linus Torvalds , Thomas Gleixner , rth@twiddle.net, Chris Zankel , tony.luck@intel.com, LKML , ralf@linux-mips.org, Marc Gauthier , lethal@linux-sh.org, schwidefsky@de.ibm.com, linux390@de.ibm.com, davem@davemloft.net, parisc-linux@parisc-linux.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Steven Rostedt wrote: > would now create a variable called per_cpu_offset__myint in > the .data.percpu_offset section. This variable will point to the (if > defined in the kernel) __per_cpu_offset[] array. If this was a module > variable, it would point to the module per_cpu_offset[] array which is > created when the modules is loaded. If I'm following you correctly, this adds another dependent load to a per-CPU data access, and from memory that isn't node-affine. If so, I think people with SMP and NUMA kernels would care more about performance and scalability than the few k of memory this saves. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com