From debbugs-submit-bounces@debbugs.gnu.org Tue Dec 13 12:19:28 2016 Received: (at 24937) by debbugs.gnu.org; 13 Dec 2016 17:19:28 +0000 Received: from localhost ([127.0.0.1]:40959 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cGqjg-0001cF-Ge for submit@debbugs.gnu.org; Tue, 13 Dec 2016 12:19:28 -0500 Received: from sinope.bbbm.mdc-berlin.de ([141.80.25.23]:42371) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1cGqjf-0001c6-8A for 24937@debbugs.gnu.org; Tue, 13 Dec 2016 12:19:28 -0500 Received: from localhost (localhost [127.0.0.1]) by sinope.bbbm.mdc-berlin.de (Postfix) with ESMTP id F2CF0A894A; Tue, 13 Dec 2016 18:19:25 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=mdc-berlin.de; h= content-transfer-encoding:content-type:content-type:mime-version :message-id:date:date:in-reply-to:subject:subject:from:from :user-agent:references:received:received:received; s=mdc; t= 1481649559; x=1483463960; bh=YMu6NtX1ZnmlGcwmhJ2Cw4MUCmkE/LX0JLt rrnfnVCA=; b=LMdVFxVUKLaAX98PEKDm5bptcC18Qbdd8k4Rs4wyaQ1oQJOVnvS RhedB4HAWFnceREd0dzTi66UAe++MtIBBYgvqBLV0EL1hSHwQBfWsO6quk0H3V3u C8uEqu7lyTzNE7tXjB4fvZJXzZSr43Sqt0naO2L1cYp210tGpG8BqlUI= X-Virus-Scanned: amavisd-new at mdc-berlin.de Received: from sinope.bbbm.mdc-berlin.de ([127.0.0.1]) by localhost (sinope.bbbm.mdc-berlin.de [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id USUQSi6KjIHv; Tue, 13 Dec 2016 18:19:19 +0100 (CET) Received: from HTCAONE.mdc-berlin.net (puck.citx.mdc-berlin.de [141.80.36.101]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by sinope.bbbm.mdc-berlin.de (Postfix) with ESMTPS; Tue, 13 Dec 2016 18:19:19 +0100 (CET) Received: from localhost (141.80.180.135) by HTCAONE.mdc-berlin.net (141.80.180.125) with Microsoft SMTP Server (TLS) id 14.3.319.2; Tue, 13 Dec 2016 18:19:18 +0100 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> User-agent: mu4e 0.9.16; emacs 25.1.1 From: Ricardo Wurmus To: Ludovic =?utf-8?Q?Court=C3=A8s?= Subject: Re: bug#24937: "deleting unused links" GC phase is too slow In-Reply-To: <87fulrsqxx.fsf@gnu.org> Date: Tue, 13 Dec 2016 18:18:57 +0100 Message-ID: <87vaunbvcu.fsf@mdc-berlin.de> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-Originating-IP: [141.80.180.135] X-TM-AS-Product-Ver: SMEX-11.0.0.4283-8.000.1202-22758.006 X-TM-AS-Result: No--0.114700-0.000000-31 X-TM-AS-MatchedID: 150567-703786-703731-139010-706249-139705-707904-861157-7 03385-105700-711664-701202-710480-701719-709009-702942-701604-700862-701296 -700756-148004-148133-42000-42003 X-TM-AS-User-Approved-Sender: Yes X-TM-AS-User-Blocked-Sender: No X-Spam-Score: -8.1 (--------) X-Debbugs-Envelope-To: 24937 Cc: Mark H Weaver , 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: -8.1 (--------) Ludovic Courtès writes: > Ricardo, Roel: would you be able to run that links-traversal.c from > > on a machine with a big store, as described at > ? I just ran this on my workstation in the office where I regularly build packages. Here’s the output of “df -i /gnu” Filesystem Inodes IUsed IFree IUse% Mounted on /dev/mapper/fedora-root 3301376 1098852 2202524 34% / Probably not large enough to derive conclusions about hydra’s behaviour. [I can’t run it on the shared store at the MDC because NFS performance is too poor. I recently ran “guix gc --optimize” to dedupe the shared store (post-build deduplication is disabled since a few weeks) and it’s at 3,197,489 used inodes.] Here are the results of running the link-traversal code on my workstation: --8<---------------cut here---------------start------------->8--- rwurmus in ~: gcc -std=gnu99 -Wall links-traversal.c -DMODE=3 rwurmus in ~: sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches' rwurmus in ~: time ./a.out 412825 dir_entries, 107 seconds stat took 0 seconds real 1m47.264s user 0m0.214s sys 0m1.314s rwurmus in ~: gcc -std=gnu99 -Wall links-traversal.c -DMODE=2 rwurmus in ~: sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches' rwurmus in ~: time ./a.out 12821 dir_entries, 107 seconds (including stat) real 1m46.475s user 0m0.201s sys 0m1.309s --8<---------------cut here---------------end--------------->8--- -- Ricardo