From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mp11.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by ms5.migadu.com with LMTPS id aEUTHAXIl2JKawAAbAwnHQ (envelope-from ) for ; Wed, 01 Jun 2022 22:11:49 +0200 Received: from aspmx1.migadu.com ([2001:41d0:8:6d80::]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) by mp11.migadu.com with LMTPS id WEn3GwXIl2JbrgAA9RJhRA (envelope-from ) for ; Wed, 01 Jun 2022 22:11:49 +0200 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by aspmx1.migadu.com (Postfix) with ESMTPS id 29D721AC1C for ; Wed, 1 Jun 2022 22:11:49 +0200 (CEST) Received: from localhost ([::1]:42310 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1nwUh1-0004Yu-TC for larch@yhetil.org; Wed, 01 Jun 2022 16:11:47 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:48988) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1nwUeb-0002y7-K3 for guix-devel@gnu.org; Wed, 01 Jun 2022 16:09:17 -0400 Received: from michel.telenet-ops.be ([2a02:1800:110:4::f00:18]:56114) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1nwUeZ-0004Ad-9Y for guix-devel@gnu.org; Wed, 01 Jun 2022 16:09:17 -0400 Received: from ptr-bvsjgyhxw7psv60dyze.18120a2.ip6.access.telenet.be ([IPv6:2a02:1811:8c09:9d00:3c5f:2eff:feb0:ba5a]) by michel.telenet-ops.be with bizsmtp id dw9B2700N4UW6Th06w9BFW; Wed, 01 Jun 2022 22:09:11 +0200 Message-ID: <6b761f22d333b0acd21f407a9f5f529aaa8b16d5.camel@telenet.be> Subject: Re: A corner case of broken reproducibility From: Maxime Devos To: Ludovic =?ISO-8859-1?Q?Court=E8s?= Cc: Felix Lechner , Guix Devel Date: Wed, 01 Jun 2022 22:09:11 +0200 In-Reply-To: <87bkvcuynd.fsf@gnu.org> References: <87leuj108h.fsf@gnu.org> <31d13a6014b14c886686bca833d926604ce3379d.camel@telenet.be> <87bkvcuynd.fsf@gnu.org> Content-Type: multipart/signed; micalg="pgp-sha512"; protocol="application/pgp-signature"; boundary="=-1gRpdLzxpQsEb9QlJXRf" User-Agent: Evolution 3.38.3-1 MIME-Version: 1.0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=telenet.be; s=r22; t=1654114151; bh=9FzBqNTpVttb2knNHL5r7QCobOEKVHURv0Nua9IA13I=; h=Subject:From:To:Cc:Date:In-Reply-To:References; b=UMOAXczVl6S7B9f3ltC5OKMNe/DGCm0HTcruTRM2vNaMD9SjaB/m889mKq3OYzb8V 5W2gPhumHvMgHZ7ubzlJNRa8e0cZm+C1MZkbHZAyDbgI6EOUgPe/abLz3/vkroEgkn 6GzST1SxIjqSo5IHBoehuSzo3YToyWQYD55b7HYo24GDLbnW8R0Cfpmwze1eu5Plue jGmcxZbU8e3632eF2DYyOsow7OPcNYXq2IAaVmeokRzixStgTtLjQDK2b8AuuJzuWo NhAZrFTs3Pml4pie589wThaeg3leK9OiT+4cbiiE5ldNAiFLUMIF/DWUQJCsvXRB/I 8TuUYp5X/qN0A== Received-SPF: pass client-ip=2a02:1800:110:4::f00:18; envelope-from=maximedevos@telenet.be; helo=michel.telenet-ops.be X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: guix-devel@gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Development of GNU Guix and the GNU System distribution." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+larch=yhetil.org@gnu.org Sender: "Guix-devel" X-Migadu-Flow: FLOW_IN X-Migadu-To: larch@yhetil.org X-Migadu-Country: US ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1654114309; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references:list-id:list-help:list-unsubscribe: list-subscribe:list-post:dkim-signature; bh=9FzBqNTpVttb2knNHL5r7QCobOEKVHURv0Nua9IA13I=; b=chiVbmQhvWZlMjor7HaDbonbb5J9VCrq9pZ/KhwOCpQuz70Ngf5VWi9KsVZWXQqmlXANDN GfGtYxiHRT2NUPawKTwoqPdKwpNVll1KLCGAlaEmIoR75Ds9Gm0o5CqgPARS3aQFvkwRZ/ Bkwy92nfo1M2FfZN1YjoXkOSLtNzb+fp0yNgMxHQnBKI6oNv5YWbNradkK68bHERXr8rws sXL4vg5o50jLIwv/mhQPk6vr3XTYiCFM+mY29sp5eZc0jSyYfGuHCpVtt083a84cW03Aoq Ve9VM8NiVWgOtN/e5GD79wQFwXyyAelnhfWh2PgUGpAMPijZv0Oq2zTOQwQ5Rw== ARC-Seal: i=1; s=key1; d=yhetil.org; t=1654114309; a=rsa-sha256; cv=none; b=uxqdgG1atQQrzzhGeREXuAudV2J0dgX95DzylHXtIB0ubbjhzRF6ZQIz1iRPQC5Hz52PYH UH9mM3a0Bobm8OTS+m/ct/gl36wR8tDDHphusR4V0HZhQTTDbzeIZEJ6cleq6fMqXb/yDL xIzaHE78Q6jdFPi2jKee5/l7SC8TWDt+sS4rH1hHsDdu8A9BGfILHO09HmGMQaCyxy7LvV pnmErBkf5rUhWlDY4P0fiH9TQVmwAndnmjplY+2Dfmn9h87rlEAmn6/Ds6F45ahlg7SS7b ME8Bdf1XVPJ+PCrvhY4E9Y8dC+pzxTRVJz78T86719M9Xo+bHV1PP35xD9uB6g== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=telenet.be header.s=r22 header.b=UMOAXczV; dmarc=pass (policy=none) header.from=telenet.be; spf=pass (aspmx1.migadu.com: domain of "guix-devel-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="guix-devel-bounces+larch=yhetil.org@gnu.org" X-Migadu-Spam-Score: -7.73 Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=telenet.be header.s=r22 header.b=UMOAXczV; dmarc=pass (policy=none) header.from=telenet.be; spf=pass (aspmx1.migadu.com: domain of "guix-devel-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="guix-devel-bounces+larch=yhetil.org@gnu.org" X-Migadu-Queue-Id: 29D721AC1C X-Spam-Score: -7.73 X-Migadu-Scanner: scn0.migadu.com X-TUID: H4+3qPyZYLaa --=-1gRpdLzxpQsEb9QlJXRf Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Ludovic Court=C3=A8s schreef op wo 01-06-2022 om 18:38 [+0200]: > There=E2=80=99s a talk by Lennart Poettering where he explains that, cont= rary to > what one might think, =E2=80=9Cchown -R $HOME=E2=80=9D turns out to be fa= st enough that > systemd-homed can do that unconditionally (off the of my head). Interesting. Taking "find $HOME > /dev/null" as an approximation of how long "chown -R $HOME" would take: $ time find . > /dev/null=20 real 0m7,066s user 0m0,427s sys 0m1,341s Assuming that =E2=80=98unconditionally =3D only chown -R $HOME if the uid o= f $HOME isn't what was expected=E2=80=99 (otherwise, +7sec for every boot), that's not too bad. That's on a SSD and not a hard disk though, I'd image it would be worse on a hard disk. Depending on the size of $HOME, it could be a lot longer though: $ time find /gnu/store > /dev/null=20 real 1m9,729s user 0m4,135s sys 0m13,840s Might still be acceptable as long as uids aren't switched too often ... Can we, as-is in Guix, assume we can modify /home/foo though? E.g. what if it's put on a separate storage medium not attached at boot. Greetings, Maxime. --=-1gRpdLzxpQsEb9QlJXRf Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part Content-Transfer-Encoding: 7bit -----BEGIN PGP SIGNATURE----- iI0EABYKADUWIQTB8z7iDFKP233XAR9J4+4iGRcl7gUCYpfHZxccbWF4aW1lZGV2 b3NAdGVsZW5ldC5iZQAKCRBJ4+4iGRcl7iQ0AQDkcWRSTc6Y69Gw3vxXDJd40BFT AqbgSJI5a7uBxekpLQD9HKNdiSi3zolKvNFHHxdklEicOVCfTudWwz7RnMNLpQc= =PRxo -----END PGP SIGNATURE----- --=-1gRpdLzxpQsEb9QlJXRf--