Date: Mon, 23 Jan 2017 02:24:57 -0500 From: Sergei Akhmatdinov <sakhmatd@riseup.net> To: freebsd-stable@freebsd.org Subject: Re: Building Kernel and World with -j Message-ID: <20170123022457.606a0d8e@riseup.net> In-Reply-To: <CAMPTd_A%2Be6JCJ8SPLGVh4M2Jb=ZLqHDWN9y8JLcVHgWO0=zJ8Q@mail.gmail.com> References: <CAMPTd_A%2Be6JCJ8SPLGVh4M2Jb=ZLqHDWN9y8JLcVHgWO0=zJ8Q@mail.gmail.com>
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[-- Attachment #1 --] On Sun, 22 Jan 2017 22:57:46 -0800 Walter Parker <walterp@gmail.com> 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). > > 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). > > Are parallel builds safe? If not, what are actual risk factors and can they > be mitigated? Not only do I use -j, I also use ccache. Another option is to use WITH_META_MODE=YES, that's where most of the 5-minute reports come from, I imagine. I haven't used it myself. My kernel takes 10 minutes with world taking about two hours. I generally just 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, -- Sergei Akhmatdinov My GPG public key: gpg --keyserver pgp.mit.edu --recv-keys AD800D99 [-- Attachment #2 --] -----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-----
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