From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751173AbdFBIax (ORCPT ); Fri, 2 Jun 2017 04:30:53 -0400 Received: from mail-wm0-f67.google.com ([74.125.82.67]:34832 "EHLO mail-wm0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751124AbdFBIau (ORCPT ); Fri, 2 Jun 2017 04:30:50 -0400 From: Jiri Slaby Subject: Re: [RFC PATCH 00/10] x86: undwarf unwinder To: Ingo Molnar , Josh Poimboeuf Cc: x86@kernel.org, linux-kernel@vger.kernel.org, live-patching@vger.kernel.org, Linus Torvalds , Andy Lutomirski , "H. Peter Anvin" , Peter Zijlstra References: <20170601060824.wv2go3adbvx5ptmt@gmail.com> <20170601115819.3twoowcnvtrfzjzr@treble> <20170601135005.zf2lidtgslfvyihs@gmail.com> <3da34815-7a4e-9f6c-ec9f-ed7bd05d8e51@suse.cz> Message-ID: <51d9cfa4-e322-9fb6-bc1f-b2c6ccc68bf8@suse.cz> Date: Fri, 2 Jun 2017 10:30:46 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <3da34815-7a4e-9f6c-ec9f-ed7bd05d8e51@suse.cz> Content-Type: text/plain; charset=iso-8859-2 Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/01/2017, 03:58 PM, Jiri Slaby wrote: > On 06/01/2017, 03:50 PM, Ingo Molnar wrote: >> That's not what I meant! The speedup comes from (hopefully) being able to disable >> CONFIG_FRAME_POINTER, which: > > BTW when you are mentioning this -- my measurements were with FP disabled. > > Is there any reasonably simple-to-use benchmark I could run with FP=y > and FP=n quickly? Nevermind, I tried 10000000 stack unwindings several times and ran netperf too. Both on the same virtual machine. On these microbenchmarks, the former performs ~ 1.03 times better, the latter ~ 1.3 times. When Mel measured the difference, it was around 10 % overall using more sophisticated benchmarks. With FP=n: # time echo 10000000 > /dev/test_dwarf real 0m6.659s user 0m0.000s sys 0m6.655s # for aa in 1 0 0 0 0; do netperf -P $aa ; done MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 47819.30 87380 16384 16384 10.00 41991.01 87380 16384 16384 10.00 43607.82 87380 16384 16384 10.00 42208.44 87380 16384 16384 10.00 44383.92 With FP=y: # time echo 10000000 > /dev/test_dwarf real 0m6.869s user 0m0.000s sys 0m6.868s # for aa in 1 0 0 0 0; do netperf -P $aa ; done MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to localhost () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 37807.90 87380 16384 16384 10.00 32246.67 87380 16384 16384 10.00 31358.76 87380 16384 16384 10.00 32450.00 87380 16384 16384 10.00 31326.70 thanks, -- js suse labs