From debbugs-submit-bounces@debbugs.gnu.org Fri Apr 17 04:16:21 2020 Received: (at 24937) by debbugs.gnu.org; 17 Apr 2020 08:16:21 +0000 Received: from localhost ([127.0.0.1]:39889 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jPMAe-0006Un-NR for submit@debbugs.gnu.org; Fri, 17 Apr 2020 04:16:20 -0400 Received: from eggs.gnu.org ([209.51.188.92]:57172) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jPMAd-0006Ub-B5 for 24937@debbugs.gnu.org; Fri, 17 Apr 2020 04:16:19 -0400 Received: from fencepost.gnu.org ([2001:470:142:3::e]:47599) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1jPMAY-0003v6-3o; Fri, 17 Apr 2020 04:16:14 -0400 Received: from [2a01:e0a:1d:7270:af76:b9b:ca24:c465] (port=43770 helo=ribbon) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1jPMAW-0007HA-Ue; Fri, 17 Apr 2020 04:16:13 -0400 From: =?utf-8?Q?Ludovic_Court=C3=A8s?= To: Ricardo Wurmus Subject: Re: bug#24937: "deleting unused links" GC phase is too slow References: <87wpg7ffbm.fsf@gnu.org> <87lgvm4lzu.fsf@gnu.org> <87twaaa6j9.fsf@netris.org> <87twaa2vjx.fsf@gnu.org> <87lgvm9sgq.fsf@netris.org> <87d1gwvgu0.fsf@gnu.org> <87wpf4yoz0.fsf@netris.org> <87fulrsqxx.fsf@gnu.org> <87vaunbvcu.fsf@mdc-berlin.de> <87ftd3muhp.fsf@elephly.net> <87eesnmrow.fsf@elephly.net> X-URL: http://www.fdn.fr/~lcourtes/ X-Revolutionary-Date: 29 Germinal an 228 de la =?utf-8?Q?R=C3=A9volution?= X-PGP-Key-ID: 0x090B11993D9AEBB5 X-PGP-Key: http://www.fdn.fr/~lcourtes/ludovic.asc X-PGP-Fingerprint: 3CE4 6455 8A84 FDC6 9DB4 0CFB 090B 1199 3D9A EBB5 X-OS: x86_64-pc-linux-gnu Date: Fri, 17 Apr 2020 10:16:09 +0200 In-Reply-To: <87eesnmrow.fsf@elephly.net> (Ricardo Wurmus's message of "Thu, 16 Apr 2020 16:27:27 +0200") Message-ID: <874ktieddi.fsf@gnu.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Spam-Score: -1.5 (-) X-Debbugs-Envelope-To: 24937 Cc: 24937@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -2.5 (--) Hi Ricardo, Thanks for running this benchmark! Ricardo Wurmus skribis: > root@hydra-guix-127 ~# ls -1 /gnu/store/.links | wc -l > 2017395 That=E2=80=99s not a lot, my laptop has 2.8M links. It=E2=80=99s interesting to see that system time remains at ~4.2s in all mo= des. So the only thing that modes 2 and 3 achieve is increasing CPU time. It=E2=80=99s as if the order in which files are stat=E2=80=99d had no impac= t on I/O performance. Ludo=E2=80=99.