On Sun, Sep 03, 2023 at 01:08:03PM -0700, Linus Torvalds wrote: > On Sun, 3 Sept 2023 at 11:49, Linus Torvalds > <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > > > > So I have no idea why you claim that "currently they have no choice". > > glibc is simply being incredibly stupid, and using newfstatat() for no > > good reason. > > Do you have any good benchmark that shows the effects of this? > > And if you do, does the attached patch (ENTIRELY UNTESTED!) fix the > silly glibc mis-feature? > "real fstat" is syscall(5, fd, &sb). Sapphire Rapids, will-it-scale, ops/s stock fstat 5088199 patched fstat 7625244 (+49%) real fstat 8540383 (+67% / +12%) It dodges lockref et al, but it does not dodge SMAP which accounts for the difference.
