From owner-freebsd-stable@freebsd.org Sun Jun 21 20:56:22 2020 Return-Path: Delivered-To: freebsd-stable@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id ECDDC332CA2 for ; Sun, 21 Jun 2020 20:56:22 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from smtp.freebsd.org (smtp.freebsd.org [IPv6:2610:1c1:1:606c::24b:4]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "smtp.freebsd.org", Issuer "Let's Encrypt Authority X3" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 49qlFf5zfCz4bkG; Sun, 21 Jun 2020 20:56:22 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from tensor.andric.com (tensor.andric.com [IPv6:2001:470:7a58:1::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "tensor.andric.com", Issuer "Let's Encrypt Authority X3" (verified OK)) (Authenticated sender: dim) by smtp.freebsd.org (Postfix) with ESMTPSA id AFC752B354; Sun, 21 Jun 2020 20:56:22 +0000 (UTC) (envelope-from dim@FreeBSD.org) Received: from [10.10.153.99] (227.31.12.93.rev.sfr.net [93.12.31.227]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by tensor.andric.com (Postfix) with ESMTPSA id 501E15647C; Sun, 21 Jun 2020 22:56:21 +0200 (CEST) From: Dimitry Andric Message-Id: Content-Type: multipart/signed; boundary="Apple-Mail=_14FB8FB1-8FDC-40F6-B043-0D6624BE7F73"; protocol="application/pgp-signature"; micalg=pgp-sha1 Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.14\)) Subject: Re: Buildworld and buildkernel with very slow compilation, recently Date: Sun, 21 Jun 2020 22:56:11 +0200 In-Reply-To: <5403888.XOh7uYVVfo@behemoth.lan> Cc: freebsd-stable@freebsd.org To: Chris Nehren References: <2D4CD117-99D0-4A03-8FBC-002CDFFE64F9@ellael.org> <5403888.XOh7uYVVfo@behemoth.lan> X-Mailer: Apple Mail (2.3445.104.14) X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 21 Jun 2020 20:56:23 -0000 --Apple-Mail=_14FB8FB1-8FDC-40F6-B043-0D6624BE7F73 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=us-ascii On 21 Jun 2020, at 14:36, Chris Nehren wrote: >=20 > On Sunday, June 21, 2020 8:11:15 AM EDT Michael Grimm wrote: >> Hi, >>=20 >> I am following FreeBSD 12.1-STABLE. >>=20 >> Clang has been upgraded to version 10.0.0 on May, 1st, and ever since = that >> time, I do observe a dramatic increase in compilation times of = building >> world, kernel and ports. I didn't benchmark the exact times, but >> compilation times are at least increased by a factor of 1.5. Nothing = has >> changed of the last month besides upgrading 12.1-Stable every other = week. >>=20 >> Has anyone else been bitten by this? >=20 > I don't have measurements to corroborate this, but here's a mailing = list > thread where folks are talking about it (split across two URLs, the OP = posted > in April and then there was a followup in May): >=20 > http://lists.llvm.org/pipermail/llvm-dev/2020-April/140938.html > https://lists.llvm.org/pipermail/llvm-dev/2020-May/141482.html >=20 > So there definitely seems to be *something* going on, and you are = indeed not > crazy. :) Indeed, there is some upstream discussion going on about this issue. There are some scenarios where people see non-negligible performance loss, but apparently not everybody suffers from it. If you build the whole ports collection, it is rather likely you may bump into it. I have personally not seen much performance difference in building world, kernel etc. One of the upstream problems is that there is not really any authoritative performance regression log being built up, so it is hard to see where such regressions were introduced. Somebody then has to spend a lot of time tracking down each and every regression, and then attempt to untangle it from the dozens of commits made around the same time. :) In any case, there is at least some attention on it now, so hopefully this will improve again. I don't think such fixes will be trivial though, so it is not likely they will land in 10.0.1. -Dimitry --Apple-Mail=_14FB8FB1-8FDC-40F6-B043-0D6624BE7F73 Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename=signature.asc Content-Type: application/pgp-signature; name=signature.asc Content-Description: Message signed with OpenPGP -----BEGIN PGP SIGNATURE----- Version: GnuPG/MacGPG2 v2.2 iF0EARECAB0WIQR6tGLSzjX8bUI5T82wXqMKLiCWowUCXu/JawAKCRCwXqMKLiCW o0YAAJ40Wqs+7gwLpPT3iPNOhbxJ2Mfs5ACeMKWYrlGLYOc4/FtfWu1Kflk1U/A= =zFw1 -----END PGP SIGNATURE----- --Apple-Mail=_14FB8FB1-8FDC-40F6-B043-0D6624BE7F73--