In our context, that's GCC which is taking care of it as the patch were sent upstream. About who is generating this, it may be Ceph but it could be some of our dependencies. And this is the major issue as we can't really fix them directly unless we influence them upstream. The more sub-modules we have the higher is the risk :( At the moment I found some in rocksdb & boost. When I discovered SOURCE_DATE_EPOCH, I stopped my investigations are making code changes when it's possible to do it this way. I think that was debian point of view too. Which is nice by the end as it allow people to have the behavior they want in the product but still gain reproducibility whithout any code change. ----- Mail original ----- De: "Nathan Cutler" <ncutler@xxxxxxx> À: "Erwan Velu" <evelu@xxxxxxxxxx>, "Ceph Development" <ceph-devel@xxxxxxxxxxxxxxx> Envoyé: Vendredi 6 Juillet 2018 11:17:48 Objet: Re: Improving the build performance > So only this part is necessary to get the ccache working better: > > export SOURCE_DATE_EPOCH=$(date +%D |date -f- +%s); Do we understand the mechanism by which setting SOURCE_DATE_EPOCH improves ccache-enabled "make check" run time? More specifically, do we know which components of our build stack are inserting timestamps into the build artifacts? cmake? gcc? Ceph itself? My impression from reading the documentation on SOURCE_DATE_EPOCH is that only the Debian versions of these tools can be relied upon to have been patched to use SOURCE_DATE_EPOCH instead of an on-the-fly generated timestamp. I'm especially interested to find out if anything _inside of Ceph_ is generating a timestamp at buildtime. That would be a Bad Thing - I enthusiastically support the sentiments expressed at [1]. Nathan [1] https://reproducible-builds.org/docs/timestamps/ -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
