On Sat, Oct 21, 2023 at 12:35:30PM -0700, John Reiser wrote: > On 10/20/23 13:23, Richard W.M. Jones wrote: > >Today I've read (twice) that the overhead of frame pointers on the > >runtime of the compiler, GCC, is 10%. This number is nonsense. The > >actual overhead is 1%, and I have done the tests that show this. > > Both the 1% and the 10% results can be valid. In particular, I have seen > variance of up to 15% in CPU time for consecutive runs of the same CPU- > saturating task on the SAME physical machine, due to the lack in Linux of > cache coloring considerations when allocating physical page frames for > virtual memory, and the resulting random affects on the performance > of the data cache. See https://en.wikipedia.org/wiki/Cache_coloring : Can you show an actual, reproducible test to prove your point? Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top _______________________________________________ devel mailing list -- devel@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe send an email to devel-leave@xxxxxxxxxxxxxxxxxxxxxxx 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@xxxxxxxxxxxxxxxxxxxxxxx Do not reply to spam, report it: https://pagure.io/fedora-infrastructure/new_issue
