Hi Jan, On Mon, Sep 28, 2020 at 05:28:57PM +0200, Jan Kratochvil wrote: > On Mon, 28 Sep 2020 12:31:59 +0200, Mark Wielaard wrote: > > I do find your statistics per package useful because they show dwz is > > in general effective by producing at least 20% (more) on-disk size > > reduction, > > I am ignoring the on-disk size, I always measure just *-debuginfo.rpm size. > > If anyone is concerned about on-disk size then Fedora should have already > enabled zlib section compression which would reduce the on-disk *.debug size > by 52.84% for the whole distro. Or even implement zstd section compression > probably with even bigger size decrease (and even lower performance hit > already low enough).
I was just discussing that recently with the Hotspot Perf GUI maintainer. And we concluded that if .debug files would be compressed then we would need an uncompressed cache somewhere. The issue with having the on-disk debuginfo files compressed is that for debugger/tracing/profiling tools it incurs an significant decompression time delay and extra memory usage. Especially for a profiling tool that only needs to quickly get a little information it is much more convenient to be able to simply mmap the .debug file, check the aranges and directly jump to the correct DIE offset. See e.g. https://github.com/KDAB/hotspot/issues/115 > So why do you mention the on-disk size now? Because I believe it is the most important benchmark. The on-disk size is not just the installed file size, but it is also the in memory size of the data structures that need to be stored and parsed. So a 20% smaller on-disk size also (roughly) means 20% less DIEs and abbrevs that need to be parsed or held into memory. Cheers, Mark _______________________________________________ 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
