From owner-freebsd-stable@freebsd.org Mon Jan 23 07:25:07 2017 Return-Path: Delivered-To: freebsd-stable@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 81AAECBD96C for ; Mon, 23 Jan 2017 07:25:07 +0000 (UTC) (envelope-from sakhmatd@riseup.net) Received: from mx1.riseup.net (mx1.riseup.net [198.252.153.129]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.riseup.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 588621A90 for ; Mon, 23 Jan 2017 07:25:06 +0000 (UTC) (envelope-from sakhmatd@riseup.net) Received: from cotinga.riseup.net (unknown [10.0.1.164]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client CN "*.riseup.net", Issuer "COMODO RSA Domain Validation Secure Server CA" (verified OK)) by mx1.riseup.net (Postfix) with ESMTPS id 395FF1A1FDE for ; Mon, 23 Jan 2017 07:25:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=riseup.net; s=squak; t=1485156300; bh=v5lxWijSOl2CHTf90FUwh4hxy7kNqvNMW1Q2BM+BvuQ=; h=Date:From:To:Subject:In-Reply-To:References:From; b=WNTYT2O83ZPNt7HW1gkceeO+yYGcCBVWlCFTy0I1C9WFdf4MzBIRZWCr/t19/CU4q APOZIo4ud+7ZhHslFv1/lRi9faaAFQzTmHdk5YiszKyJsTrdmw/SQ4dJHQd6ffGNbw VDMEd+Y5A5hBRG/r77u5+D+S/MQp0pFCbPJGdmw4= Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: sakhmatd) with ESMTPSA id 97024402C0 Date: Mon, 23 Jan 2017 02:24:57 -0500 From: Sergei Akhmatdinov To: freebsd-stable@freebsd.org Subject: Re: Building Kernel and World with -j Message-ID: <20170123022457.606a0d8e@riseup.net> In-Reply-To: References: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; boundary="Sig_/IdMhN4t3V.fvQqn/KOhu_BE"; protocol="application/pgp-signature" X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Jan 2017 07:25:07 -0000 --Sig_/IdMhN4t3V.fvQqn/KOhu_BE Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Sun, 22 Jan 2017 22:57:46 -0800 Walter Parker wrote: > For decades there has always been a warning not to do parallel builds of > the kernel or the world (Linux kernel builds also suggest not to do this). >=20 > Every once in a while, I see people post about 5 minutes. This only way I > can see this happening is by doing a parallel build (-j 16 on a Xeon > Monster box). >=20 > Are parallel builds safe? If not, what are actual risk factors and can th= ey > be mitigated? Not only do I use -j, I also use ccache. Another option is to use WITH_META_MODE=3DYES, that's where most of the 5-m= inute reports come from, I imagine. I haven't used it myself. My kernel takes 10 minutes with world taking about two hours. I generally j= ust leave them building overnight. The risks of parallel builds are mostly in the past, concurrency was still = just coming out and there were chances that something would get compiled before = it's dependency, breaking your compile and wasting all of those hours. Cheers, --=20 Sergei Akhmatdinov My GPG public key: gpg --keyserver pgp.mit.edu --recv-keys AD800D99 --Sig_/IdMhN4t3V.fvQqn/KOhu_BE Content-Type: application/pgp-signature Content-Description: OpenPGP digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEFByDSlcPK9lAgiNNxKRHP62ADZkFAliFr8kACgkQxKRHP62A DZloCQ//bdpk8xRxqIYD8JegqNnrpxQFysipHQQXXlfFl+lOpXOQfY/0b941nqAA cLq5fN7lA6tzfNUpoZ0enDydgYnnqccD1JBjUFZgf2V68H2C4sFIx5E2iGRfPwHg ZRhh3/v/CsZ9ED3L+aZ+oBNuJCEk/luW1Mi1OxRBXXN7r4H4kMIb48i5fV2BDped y0QdCvrvsZBq+yzDZy12An7ZBtFEQyHUW1htZHRQX1jF4Q+dM8D57OYskXc75756 tlliEkwN1ieqs1fAMSNkkFtBCVhPfHPmgvfw07LTdKkaz08vh52MKSwYZXpxZH9Z b1cpFQbysuNMh2gtAYKmPjhSXpqRvvwGaDMD7PKPvDKRQ1GDSg6/4gypaJNR3tqq 6kdK0VcOgJZj8h1DrJemncoG59y9rzy1uP3HlmhKaKCVVaiTQW+MJ8Nk7Fy3aOH3 LrJjrcSfnLFsyj6f4+U5CtWw7cvmg3vzBHJknZ8ORuZEfdlKZvoxvn5jhFoqcwQA UVyxEeEbKmFhQeJ0aYyo8ER5zrWWoqgVhilIv7pjlXO29ByDeFXQqDCZquK3bmp0 izmRvAldQ7v6heNLoz3LOHVNSDg78DqtoaEhUDmH5xMekYBySRzIwnu6HbDyIe8R cPRXLgXeaYmLD2BAmoE83j5fSDvMwGWQC2nGSW646uyt/NV5u7M= =+vbQ -----END PGP SIGNATURE----- --Sig_/IdMhN4t3V.fvQqn/KOhu_BE--