From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christopher Baines Subject: Re: Performance issues with /gnu/store in virtual machines Date: Tue, 22 Aug 2017 12:20:34 +0100 Message-ID: <20170822122034.6879df0e@cbaines.net> References: <20170817210547.3fafde57@cbaines.net> <87shgj7vz4.fsf@gnu.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; boundary="Sig_/05Gs_REDH_Zvx5FC.925Dg4"; protocol="application/pgp-signature" Return-path: Received: from eggs.gnu.org ([2001:4830:134:3::10]:53303) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dk7Ej-0001w4-JM for help-guix@gnu.org; Tue, 22 Aug 2017 07:20:46 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dk7Eg-00058h-Cq for help-guix@gnu.org; Tue, 22 Aug 2017 07:20:45 -0400 Received: from li622-129.members.linode.com ([212.71.249.129]:60916 helo=mira.cbaines.net) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dk7Eg-00057k-6x for help-guix@gnu.org; Tue, 22 Aug 2017 07:20:42 -0400 In-Reply-To: <87shgj7vz4.fsf@gnu.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: help-guix-bounces+gcggh-help-guix=m.gmane.org@gnu.org Sender: "Help-Guix" To: Ludovic =?UTF-8?B?Q291cnTDqHM=?= Cc: help-guix@gnu.org --Sig_/05Gs_REDH_Zvx5FC.925Dg4 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On Tue, 22 Aug 2017 12:11:43 +0200 ludo@gnu.org (Ludovic Court=C3=A8s) wrote: > Hi Chris, >=20 > Christopher Baines skribis: >=20 > > 1.13 0.000019 0 3853 openat =20 >=20 > [...] >=20 > > 13.56 0.193014 50 3853 openat =20 >=20 > So openat(2) is 4 orders of magnitude slower in the VM, which is a > problem. >=20 > I guess a large part of that is due to the fact that VM created with > =E2=80=98guix system vm=E2=80=99 use unionfs as their root file system, w= hich is a > FUSE thing (see the =E2=80=9Cvolatile=E2=80=9D options in (gnu system vm)= , (gnu system > linux-initrd), and (gnu build linux-boot).) I=E2=80=99m not sure how we = could > avoid it. I'm unsure if the unionfs will be involved though, as find is searching in the /gnu/store directory, which is shared with the host: TAG_gnu_store on /gnu/store type 9p (ro,relatime,sync,dirsync,trans=3Dvir= tio) This might be misunderstanding how mounts work, but this could be either layered on top, or below the unionfs, and I'm guessing its on top, which in my mind would mean that the unionfs isn't involved? > Can you confirm that the same =E2=80=98find=E2=80=99 command is faster in= a full-blown > =E2=80=9Cguix system disk-image=E2=80=9D VM? Yep, I see 8 usecs/call (compared to 50). --Sig_/05Gs_REDH_Zvx5FC.925Dg4 Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQKTBAEBCgB9FiEEPonu50WOcg2XVOCyXiijOwuE9XcFAlmcE4JfFIAAAAAALgAo aXNzdWVyLWZwckBub3RhdGlvbnMub3BlbnBncC5maWZ0aGhvcnNlbWFuLm5ldDNF ODlFRUU3NDU4RTcyMEQ5NzU0RTBCMjVFMjhBMzNCMEI4NEY1NzcACgkQXiijOwuE 9XdyDA//ZSbhIuE+n6Jj8lYZhTsNkULmMNtzelcjCs+tch/VFgsz8Bp5HftBY4ec vLsZkBqYRbpD7I99DE5+KPNEPvqdmMslpkwW6jBJ8AZ9hmRTcvo0AEd63V7d1+mc 1c0MvgMHMBGmePDzLadGDzA0OVnLLYX4CGYe82gw0VxlPnWRVLjc4fT8wYSsFYE7 z6fbBmk5gvJ8lq6BUzo9gDk5pEglFiZ7GqFvFtzqqiox0e9V40WZYjnU/7bqkSiH fGu9VYGv67Gnt3JyR6Dn3j7wLESgD2CLfECvXE1/8kVYEkLlpcJ3ZB+jXmFJlHr+ MOGtGeFZ6w9kG4DSOZEHImm9M+cPQ6GiMmu0KU/kYwWJAHlmVz3SaWNOxfwapisS apUQrg1XdqBoskx2srNJDHPT2xROA3jithQWt07NQchyFZtxH/iqYXyGCyIhodVr j8pTPQEbmXxZzj+0Y/PVIARHOEbYoqMkbX33xnIfNzDJCAt4Oti355/tRCT+59yQ D5WU45Oux9KMKAUMfGh6eaOzdj7ULiE9/h3JG3j3RGJ0u3jWnNNGn4GkUl920ZXn ezPNiRv8UlJlRI5r37/L+LQFd6njumMzZRo0Kd2MTkO7YVoJ8r4jNAkoow4YtuD7 G+C/z/GgsA6TaDu/WuciGZEzzEnciKAWHNx+yi1cuw4zd+fzk84= =XJfy -----END PGP SIGNATURE----- --Sig_/05Gs_REDH_Zvx5FC.925Dg4--