On Wed, Jan 03, 2018 at 11:50:28PM +0100, Lukas Tribus wrote: > > I've always been all for supporting older compilers exactly for the > > reason above. Till very recently, gcc-2.95 was still reported to work ;-) > > I also have to say that I consider thread support to be a > "high-performance" feature, and I would not personally consider > pairing such high-performance features with a obsolete OS like CentOs > 6. I mean ... we are talking linux 2.6.32 (I heard even 2.6.32's > maintainer pulled the plug last year :) )
Sure but the same can be said for other operating systems as well. CentOS 6 is still supported by its vendor (till end of 2020) so unless we have a good reason (technical difficulty, incompatibility, etc), we should at least check if it can be done. For me the only reason is that the newer version of the atomic_* builtins were used while we used to use the older version in the shctx code. It's very possible the older version doesn't exist anymore in newer compilers. But if it's just a matter of adding a #ifdef, it will not take a long time to check. > The reason we see this build failure is that we implicitly added > USE_THREADS=1 in the linux2628 make target. Perhaps we just need a new > make target with something more recent and move threads support to it. > However it's also true that without implicitly enabling threads in the > linux2628 target we would have never seen the amount of feedback for > thread issues that we saw, and most of the bugs would probably still > be unfixed at this point. Exactly. I'd rather encourage everyone to enable all features by default so that we can add options to disable what is known broken, than slowly discovering what works and making people believe there are few features. > In any case, I would avoid complicating the codebase and/or investing > a lot of time to bring thread support to CentOS 6, I'd rather keep it > simple and disable thread support for it by default (whether via > different make targets or by other means). I totally agree and my point really is not to make anything complicated nor to take risks. Oh and now I have a good incentive to look at this, my home NFS server also runs gcc 4.4 and doesn't build threads ;-) Willy
