On Sat, 23 May 2020 at 23:35, Andi Kleen <a...@linux.intel.com> wrote: > > Anand K Mistry <amis...@google.com> writes: > > } > > > > + done_fd = eventfd(0, EFD_NONBLOCK); > > This will make perf depend on a recent glibc or other library > that implements eventfd. Wouldn't surprise me if some kind > of build time check is needed for this to pass all of Arnaldo's > built tests.
Looks like Arnaldo made that change when merging: https://git.kernel.org/pub/scm/linux/kernel/git/acme/linux.git/commit/?h=perf/core&id=e9db221d37f91409040cf7f3fbed08b44e055ae9 This makes me curious. How old a kernel should modern tools support? >From the man page, eventfd was added in 2.6.22 (and eventfd2 in 2.6.27), which was 2007 (or 2008 for eventfd2) and glibc-2.8 which was 2008. I understand the kernel's policy of never breaking userspace, but what about userspace tools? > > > -Andi -- Anand K. Mistry Software Engineer Google Australia
