Comment 7 for bug 1663280

I don't see anywhere near the performance degradation you're seeing, so it must be heavily dependent on the family and stepping that you're using.

e.g.
[carlos@athas rhbz1421121]$ time LD_BIND_NOW=1 ./pow-test
154964150.331550

real 0m1.831s
user 0m1.820s
sys 0m0.003s

[carlos@athas rhbz1421121]$ time ./pow-test
154964150.331550

real 0m1.830s
user 0m1.820s
sys 0m0.001s

Verified pow-test built without DT_FLAGS BIND_NOW.

I agree that it is less than optimal to have processor state transitions like those you indicate for every time the dynamic loader trampoline is called.

We'll look into this.

Fedora 26 will not have this problem since it's based on glibc 2.25 with the fix you indicate already present.