On Fri, 2019-11-15 at 16:28 +0100, Miro Hrončok wrote: > On 15. 11. 19 16:20, Vít Ondruch wrote: > > Dne 15. 11. 19 v 15:51 David Malcolm napsal(a): > > > On Fri, 2019-11-15 at 12:31 +0000, Daniel P. Berrangé wrote: > > > > On Fri, Nov 15, 2019 at 01:23:09PM +0100, Miroslav Suchý wrote: > > > > > Dne 15. 11. 19 v 10:21 Victor Stinner napsal(a): > > > > > > I'm not sure if we need a Fedora change just for a compiler > > > > > > flag. > > > > > > Again, the only drawback is that we will no longer be able > > > > > > to > > > > > > override a symbol using LD_PRELOAD. Honestly, I never did > > > > > > that. I > > > > > > don't see any use case for that. But I used LD_PRELOAD on > > > > > > the > > > > > > libc multiple times to mock the system clock for example. > > > > > > > > > > > > If someone really needs LD_PRELOAD, it's quite easy to > > > > > > build a > > > > > > custom Python without -fno-semantic-interposition. > > > > > Mock's Nosync plugin use LD_PRELOAD: > > > > > https://github.com/rpm-software-management/mock/wiki/Feature-nosync > > > > IIUC mock would not be affected by this change. > > > > > > > > The LD_PRELOAD limitation described applies to symbols that are > > > > in > > > > the libpython.so library. > > > > > > > > Those docs suggest mock is replacing the fsync() API in glibc > > > > with > > > > its > > > > LD_PRELOAD, so that should continue to work as normal. > > > > > > > > Regards, > > > > Daniel > > > Thinking aloud: does anyone ever use symbol overriding for > > > anything > > > other than glibc? > > > > > > What would it do to distro-wide performance if > > > -fno-semantic-interposition > > > were added to the default rpm build flags, (and glibc added > > > -fsemantic- > > > interposition to override this)? > > > > > > Basically, change the default distro-wide to libraries opting-in > > > to > > > being able to be interposed, rather than opting-out (-fsemantic- > > > interposition appears to be on by default, looking at the source > > > for > > > gcc). > > > > +1 > > > > Because this was from the beginning my concern. Why do it just for > > Python if possibly the whole distribution could benefit. > > I'm not saying we shouldn't. It's a good idea (to explore). > > Why not start with Python and if it proves working, continue form > there? > > The benefit is that in Python, we would handle the Python change and > the revert > would be just one package, in case unforeseen problems occur.
Indeed, it would be a massive scope creep compared to your feature; I just thought it worth mentioning as an idea - I don't want to derail your work (and thanks for speeding up python!) Dave _______________________________________________ devel mailing list -- devel@lists.fedoraproject.org To unsubscribe send an email to devel-le...@lists.fedoraproject.org Fedora Code of Conduct: https://docs.fedoraproject.org/en-US/project/code-of-conduct/ List Guidelines: https://fedoraproject.org/wiki/Mailing_list_guidelines List Archives: https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org
