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Message-ID: <20190102230054.m5ire5gdhm5fzecq@ca-dmjordan1.us.oracle.com>
Date: Wed, 2 Jan 2019 15:00:54 -0800
From: Daniel Jordan <daniel.m.jordan@...cle.com>
To: Yang Shi <yang.shi@...ux.alibaba.com>
Cc: ying.huang@...el.com, tim.c.chen@...el.com, minchan@...nel.org,
akpm@...ux-foundation.org, linux-mm@...ck.org,
linux-kernel@...r.kernel.org
Subject: Re: [v4 PATCH 1/2] mm: swap: check if swap backing device is
congested or not
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.
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