* Linus Torvalds <torva...@linux-foundation.org> wrote:
> On Tue, Mar 5, 2019 at 4:03 AM Ingo Molnar <mi...@kernel.org> wrote: > > > > Please pull the latest core-rcu-for-linus git tree from: > > > > git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git > > core-rcu-for-linus > > Hmm. I think this made my build time explode. > > I'm bisecting, but it looks like my allmodconfig builds went from ~31 > min to ~39 min with this pull. > > NOTE! I'm not saying that the kernel slowed down. Just the *build* > (with the same kernel) slowed down. > > It's odd, and maybe I did something wrong, so I'll have to > double-check the numbers, but I thought I'd mention it in case > somebody goes "Ahh, I did X to the include files, so now every > compiler invocation probably sees all of xyz and that will slow things > down enormously". Could it be the locking tree? In particular the atomics auto-generation slowed down the build before, but this build regression was thought to be fixed with: 0cf264b3133d: locking/atomics: Check atomic headers with sha1sum but maybe that's not the whole story? Or it's an unreported slowdown related to the RCU tree, as you say. Thanks, Ingo