Date: Sat, 22 May 2021 19:05:56 -0700 From: Mark Millard via freebsd-arm <freebsd-arm@freebsd.org> To: tech-lists <tech-lists@zyxst.net> Cc: freebsd-arm <freebsd-arm@freebsd.org> Subject: Re: RPi 4 build time Message-ID: <508F89DF-5CA5-4608-91E7-B232708BDC7C@yahoo.com> In-Reply-To: <DA22CB96-82BE-4AAB-BB94-500E4B1AB1BB@yahoo.com> References: <YKgTB7Hf3dkQiW5c@vax.khramtsov.org> <YKgzeLxxZNhViwoi@ceres.zyxst.net> <0299DFBF-5497-4A06-978D-13E4FBD8B5F0@yahoo.com> <YKkqxrthZoHg87wV@ceres.zyxst.net> <DB0011CC-3F99-4E34-B5DF-307AD707851A@yahoo.com> <9A949E36-FDF2-40B3-A126-5538E41964D3@yahoo.com> <YKmuk97mO2trodFp@ceres.zyxst.net> <DA22CB96-82BE-4AAB-BB94-500E4B1AB1BB@yahoo.com>
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On 2021-May-22, at 18:36, Mark Millard via freebsd-arm <freebsd-arm at = freebsd.org> wrote: > On 2021-May-22, at 18:23, tech-lists <tech-lists at zyxst.net> wrote: >=20 >> On Sat, May 22, 2021 at 04:51:31PM -0700, Mark Millard via = freebsd-arm wrote: >>=20 >>> In general these figures are approximations of the low >>> bound on a buildworld that is a (near) no-op but is >>> not frequently approached in my normal activity. But >>> it is rare for me to update the source tree again >>> and rebuild after only a few source commits after >>> what was originally rebuilt. For such, sub-half hour >>> rebuilds can certainly occur via META_MODE use. >>>=20 >>> The context happened to be the ZFS based one in all >>> cases. Still no ccache use. >>=20 >> That's wild. I have to look at meta mode.=20 >> My use case though mostly involves building/updating ports with >> poudriere, and I'm happy it can use ccache. >>=20 >> Am I right in thinking meta mode is a buildworld/kernel thing only? = I've >> only heard of it; I know nothing about it. >=20 > Yep: buildworld buildkernel only. >=20 > META_MODE does not help for after a "rm -rf /usr/obj/*" > sort of clean-out. It just attempts to avoid rebuilding > materials already present that are sufficient. (It still > builds more than is strictly necessary: Some of the > dependency tracking tracks things that do not actually > imply needing a file rebuild. This is why installworld > to the live system ends up leading to a larger rebuild > later.) >=20 I should have also mentioned the other side of META_MODE: It is there to also be sure to rebuild things that do need to be rebuilt. Its rebuilding more than necessary generally avoids ending up with insufficient/inaccurate rebuilds. Between ending up with false positives vs. false negatives, it has a definite bias. =3D=3D=3D Mark Millard marklmi at yahoo.com ( dsl-only.net went away in early 2018-Mar)
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