From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qt1-f199.google.com (mail-qt1-f199.google.com [209.85.160.199]) by kanga.kvack.org (Postfix) with ESMTP id 6A58D8E0002 for ; Wed, 2 Jan 2019 18:00:50 -0500 (EST) Received: by mail-qt1-f199.google.com with SMTP id m37so40274270qte.10 for ; Wed, 02 Jan 2019 15:00:50 -0800 (PST) Received: from userp2130.oracle.com (userp2130.oracle.com. [156.151.31.86]) by mx.google.com with ESMTPS id z64si257424qke.271.2019.01.02.15.00.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 02 Jan 2019 15:00:49 -0800 (PST) Date: Wed, 2 Jan 2019 15:00:54 -0800 From: Daniel Jordan Subject: Re: [v4 PATCH 1/2] mm: swap: check if swap backing device is congested or not Message-ID: <20190102230054.m5ire5gdhm5fzecq@ca-dmjordan1.us.oracle.com> References: <1546145375-793-1-git-send-email-yang.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1546145375-793-1-git-send-email-yang.shi@linux.alibaba.com> Sender: owner-linux-mm@kvack.org List-ID: To: Yang Shi Cc: ying.huang@intel.com, tim.c.chen@intel.com, minchan@kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org On Sun, Dec 30, 2018 at 12:49:34PM +0800, Yang Shi wrote: > The test on my virtual machine with congested HDD shows long tail > latency is reduced significantly. > > Without the patch > page_fault1_thr-1490 [023] 129.311706: funcgraph_entry: #57377.796 us | do_swap_page(); > page_fault1_thr-1490 [023] 129.369103: funcgraph_entry: 5.642us | do_swap_page(); > page_fault1_thr-1490 [023] 129.369119: funcgraph_entry: #1289.592 us | do_swap_page(); > page_fault1_thr-1490 [023] 129.370411: funcgraph_entry: 4.957us | do_swap_page(); > page_fault1_thr-1490 [023] 129.370419: funcgraph_entry: 1.940us | do_swap_page(); > page_fault1_thr-1490 [023] 129.378847: funcgraph_entry: #1411.385 us | do_swap_page(); > page_fault1_thr-1490 [023] 129.380262: funcgraph_entry: 3.916us | do_swap_page(); > page_fault1_thr-1490 [023] 129.380275: funcgraph_entry: #4287.751 us | do_swap_page(); > > With the patch > runtest.py-1417 [020] 301.925911: funcgraph_entry: #9870.146 us | do_swap_page(); > runtest.py-1417 [020] 301.935785: funcgraph_entry: 9.802us | do_swap_page(); > runtest.py-1417 [020] 301.935799: funcgraph_entry: 3.551us | do_swap_page(); > runtest.py-1417 [020] 301.935806: funcgraph_entry: 2.142us | do_swap_page(); > runtest.py-1417 [020] 301.935853: funcgraph_entry: 6.938us | do_swap_page(); > runtest.py-1417 [020] 301.935864: funcgraph_entry: 3.765us | do_swap_page(); > runtest.py-1417 [020] 301.935871: funcgraph_entry: 3.600us | do_swap_page(); > runtest.py-1417 [020] 301.935878: funcgraph_entry: 7.202us | do_swap_page(); Hi Yang, I guess runtest.py just calls page_fault1_thr? Being explicit about this may improve the changelog for those unfamiliar with will-it-scale. May also be useful to name will-it-scale and how it was run (#thr, runtime, system cpus/memory/swap) for more context.