Chris Nehren
2020-Jun-21 12:36 UTC
Buildworld and buildkernel with very slow compilation, recently
On Sunday, June 21, 2020 8:11:15 AM EDT Michael Grimm wrote:> Hi, > > I am following FreeBSD 12.1-STABLE. > > 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. > > Has anyone else been bitten by this?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): http://lists.llvm.org/pipermail/llvm-dev/2020-April/140938.html https://lists.llvm.org/pipermail/llvm-dev/2020-May/141482.html So there definitely seems to be *something* going on, and you are indeed not crazy. :)
Dimitry Andric
2020-Jun-21 20:56 UTC
Buildworld and buildkernel with very slow compilation, recently
On 21 Jun 2020, at 14:36, Chris Nehren <cnehren at pobox.com> wrote:> > On Sunday, June 21, 2020 8:11:15 AM EDT Michael Grimm wrote: >> Hi, >> >> I am following FreeBSD 12.1-STABLE. >> >> 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. >> >> Has anyone else been bitten by this? > > 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): > > http://lists.llvm.org/pipermail/llvm-dev/2020-April/140938.html > https://lists.llvm.org/pipermail/llvm-dev/2020-May/141482.html > > 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 -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 223 bytes Desc: Message signed with OpenPGP URL: <http://lists.freebsd.org/pipermail/freebsd-stable/attachments/20200621/48dccc0f/attachment.sig>