Hello, On Fri, Aug 05 2022, Dan Čermák wrote:
dieter
writes: Hi,
On Thu, 04 Aug 2022 18:40:23 +0200 Martin Jambor wrote:
Are there some data available about the actual benefit of this change?
Over the weekend, I have quickly gathered some SPEC CPU benchmarks results comparing the different x86_64 versions:
thanks, very interesting results. I admit this gain is even less than I expected.
Yes, the gain is small, but a few percent gain will result in e.g. HPC users to pick another distribution. But yeah, the gain in these benchmarks is really surprisingly small.
please note that I measured SPEC only because I already have the setup to run it quickly and then compare the results. The results show some benefits, for example the improvements in 531.deepsjeng_r is most likely because of POPCNT and the software you use may contain more such opportunities to utilize these "new" instructions. And I do think that at some point old HW just should not be considered a blocker to progress - and more than a decade seems like old to me. But while I am myself somewhat undecided about switching to -v2, I would like the openSUSE community to look at the -v3 improvements too, because the floating-point ones are IMHO big. ImageMagick alone runs 20% faster and that means that compiling for older HW wastes a lot of compute power (and thus a lot of energy too) on new machines. Can we estimate when we will want to switch to -v3? (I assume we don't want to do it now.) In two years? Four years? Six years? Never? I think that arriving at some consensus would benefit not just planners at both openSUSE and SUSE but also users still relying on machines that do not support -v3 (I regularly use one too and also would like to keep it for a few more years :-). Thank you, Martin