From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.1 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,PLING_QUERY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id F41FAC433DF for ; Fri, 12 Jun 2020 22:45:39 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 7D8BC206DC for ; Fri, 12 Jun 2020 22:45:39 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D8BC206DC Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=ucw.cz Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EE8828D00D7; Fri, 12 Jun 2020 18:45:38 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E97F68D00A0; Fri, 12 Jun 2020 18:45:38 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DAE6A8D00D7; Fri, 12 Jun 2020 18:45:38 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id C59958D00A0 for ; Fri, 12 Jun 2020 18:45:38 -0400 (EDT) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 81DDC180AD817 for ; Fri, 12 Jun 2020 22:45:38 +0000 (UTC) X-FDA: 76922043156.18.shape88_4f1287726de0 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin18.hostedemail.com (Postfix) with ESMTP id 60C29100ED9C6 for ; Fri, 12 Jun 2020 22:45:38 +0000 (UTC) X-HE-Tag: shape88_4f1287726de0 X-Filterd-Recvd-Size: 3457 Received: from jabberwock.ucw.cz (jabberwock.ucw.cz [46.255.230.98]) by imf48.hostedemail.com (Postfix) with ESMTP for ; Fri, 12 Jun 2020 22:45:37 +0000 (UTC) Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id 1D38C1C0C0A; Sat, 13 Jun 2020 00:45:35 +0200 (CEST) Date: Sat, 13 Jun 2020 00:45:33 +0200 From: Pavel Machek To: Vlastimil Babka Cc: kernel list , Andrew Morton , mhocko@suse.cz, "linux-mm@kvack.org" Subject: Re: 5.7-rc0: kswapd eats cpu during a disk test?! Message-ID: <20200612224532.GA24103@amd> References: <20200531103431.GA28429@amd> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="ZGiS0Q5IWpPtfppv" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) X-Rspamd-Queue-Id: 60C29100ED9C6 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam01 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --ZGiS0Q5IWpPtfppv Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > +CC linux-mm >=20 > On 5/31/20 12:34 PM, Pavel Machek wrote: > > Hi! > >=20 > > This is simple cat /dev/sda > /dev/zero... on thinkpad x60 (x86-32), > > with spinning rust. > >=20 > > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ CO= MMAND > > 1000 root 20 0 0 0 0 R 53.3 0.0 57:34.93 = kswapd0 > > 27897 root 20 0 6976 580 536 R 44.5 0.0 1:44.53 = cat > >=20 > > It keeps both CPUs busy... and I don't think that's right. >=20 > Does an older kernel behave differently here? Let me try on x220 (x86-64, first): 737 root 20 0 5404 744 680 R 31.2 0.0 0:09.98 cat = =20 1024 root 20 0 0 0 0 S 21.4 0.0 165:22.68 kswapd= 0 =20 That was with ssd, result with spinning rust is similar: 859 root 20 0 5404 740 672 D 21.1 0.0 0:03.33 cat = =20 1024 root 20 0 0 0 0 R 11.8 0.0 165:33.07 kswapd= 0 =20 5.7-rc1+ kernel. Performance of spinning rust is down, too, on x60: pavel@amd:~/misc/hw/hdd1t$ sudo ddrescue --force /dev/sda1 /dev/null GNU ddrescue 1.19 Press Ctrl-C to interrupt rescued: 2147 MB, errsize: 0 B, current rate: 3080 kB/s ipos: 2147 MB, errors: 0, average rate: 5382 kB/s opos: 2147 MB, run time: 6.65 m, successful read: 0 s ago Finished pavel@amd:~/misc/hw/hdd1t$ uname -a Linux amd 5.7.0-next-20200611+ #123 SMP PREEMPT Thu Jun 11 15:41:22 CEST 2020 i686 GNU/Linux And there's something clearly wrong here: 966 root 20 0 0 0 0 R 94.4 0.0 8:18.82 kswap= d0 23933 root 20 0 4612 1112 1028 D 80.6 0.0 0:26.40 ddr= escue =20 --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --ZGiS0Q5IWpPtfppv Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAl7kBYwACgkQMOfwapXb+vLueACeO3gC3MnrW9iGKiyH8QVDEmfj h6gAn3S/b5S1hCuvVVuw90VLs07B8/PY =WYoU -----END PGP SIGNATURE----- --ZGiS0Q5IWpPtfppv--