Improve string benchtest timing. Many tests run for 0.01s which is way too
short to give accurate results. Other tests take over 40 seconds which is
way too long. Significantly increase the iterations of the short running
tests. Reduce number of alignment variations in the long running memcpy walk
tests so they take less than 5 seconds.
As a result most tests take at least 0.1s and all finish within 5 seconds.
* benchtests/bench-memcpy-random.c (do_one_test): Use medium iterations.
* benchtests/bench-memcpy-walk.c (test_main): Reduce alignment tests.
* benchtests/bench-memmem.c (do_one_test): Use small iterations.
* benchtests/bench-memmove-walk.c (test_main): Reduce alignment tests.
* benchtests/bench-memset-walk.c (test_main): Reduce alignment tests.
* benchtests/bench-strcasestr.c (do_one_test): Use small iterations.
* benchtests/bench-string.h (INNER_LOOP_ITERS): Increase iterations.
(INNER_LOOP_ITERS_MEDIUM): New define.
(INNER_LOOP_ITERS_SMALL): New define.
* benchtests/bench-strpbrk.c (do_one_test): Use medium iterations.
* benchtests/bench-strsep.c (do_one_test): Use small iterations.
* benchtests/bench-strspn.c (do_one_test): Use medium iterations.
* benchtests/bench-strstr.c (do_one_test): Use small iterations.
* benchtests/bench-strtok.c (do_one_test): Use small iterations.
Currently the benchtests are run with internal GLIBC headers, which is incorrect.
Defining _ISOMAC in the makefile ensures the internal headers are bypassed.
Fix all tests which were relying on internal defines or includes.
* benchtests/Makefile: Define _ISOMAC.
* benchtests/bench-strcoll.c: Add missing sys/stat.h include.
* benchtests/bench-string.h: Define inhibit_loop_to_libcall macro.
* benchtests/bench-strstr.c: Define empty libc_hidden_builtin_def.
* benchtests/bench-strtok.c (oldstrtok): Use rawmemchr.
* benchtests/bench-timing.h: Define attribute_hidden.
calls strcspn, call strcspn directly so we get the end of the token without
an extra call to rawmemchr. Also avoid an unnecessary call to strcspn after
the last token by adding an early exit for an empty string. Change strtok
to tailcall strtok_r to avoid unnecessary code duplication.
Remove the special header optimization for strtok_r of a 1-character
constant string - both strspn and strcspn contain optimizations for this
case. Benchmarking this showed similar performance in the worst case,
but up to 5.5x better performance in the "found" case for large inputs.
* benchtests/bench-strtok.c (oldstrtok): Add old implementation.
* string/strtok.c (strtok): Change to tailcall __strtok_r.
* string/strtok_r.c (__strtok_r): Optimize for performance.
* string/string-inlines.c (__old_strtok_r_1c): New function.
* string/bits/string2.h (__strtok_r): Move to string-inlines.c.
