From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from g1t6214.austin.hp.com ([15.73.96.122]:58238 "EHLO g1t6214.austin.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932212AbcBAWD6 (ORCPT ); Mon, 1 Feb 2016 17:03:58 -0500 Message-ID: <56AFD649.9030707@hpe.com> Date: Mon, 01 Feb 2016 17:03:53 -0500 From: Waiman Long MIME-Version: 1.0 To: Andi Kleen CC: Ingo Molnar , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Alexander Viro , linux-fsdevel@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Scott J Norton , Douglas Hatch Subject: Re: [PATCH v2 3/3] vfs: Enable list batching for the superblock's inode list References: <1454095846-19628-1-git-send-email-Waiman.Long@hpe.com> <1454095846-19628-4-git-send-email-Waiman.Long@hpe.com> <20160130083557.GA31749@gmail.com> <20160201174526.GA3696@two.firstfloor.org> In-Reply-To: <20160201174526.GA3696@two.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-fsdevel-owner@vger.kernel.org List-ID: On 02/01/2016 12:45 PM, Andi Kleen wrote: >> I'm wondering, why are inode_sb_list_add()/del() even called for a presumably >> reasonably well cached benchmark running on a system with enough RAM? Are these >> perhaps thousands of temporary files, already deleted, and released when all the >> file descriptors are closed as part of sys_exit()? >> >> If that's the case then I suspect an even bigger win would be not just to batch >> the (sb-)global list fiddling, but to potentially turn the sb list into a >> percpu_alloc() managed set of per CPU lists? It's a bigger change, but it could > We had such a patch in the lock elision patchkit (It avoided a lot > of cache line bouncing leading to aborts) > > https://git.kernel.org/cgit/linux/kernel/git/ak/linux-misc.git/commit/?h=hle315/combined&id=f1cf9e715a40f44086662ae3b29f123cf059cbf4 > > -Andi > > I like your patch though it cannot be applied cleanly for the current upstream kernel. I will port it to the current kernel and run my microbenchmark to see what performance gain I can get. Cheers, Longman