d/freebsd-dev
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity
710e45c4b8
freebsd-dev/sys/libkern
History
Mateusz Guzik 710e45c4b8 Reimplement strlen 
The previous code neglected to use primitives which can find the end
of the string without having to branch on every character.

While here augment the somewhat misleading commentary -- strlen as
implemented here leaves performance on the table, especially so for
userspace. Every arch should get a dedicated variant instead.

In the meantime this commit lessens the problem.

Tested with glibc test suite.

Naive test just calling strlen in a loop on Haswell (ops/s):

$(perl -e "print 'A' x 3"):
before:	211198039
after:	338626619

$(perl -e "print 'A' x 100"):
before:	83151997
after:	98285919
2021-01-29 23:48:26 +00:00
..
arm Remove obsolete code gated on _ARM_ARCH_* 2021-01-28 10:41:45 +00:00
arm64
x86 Separate kernel crc32() implementation to its own header (gsb_crc32.h) and 2019-06-17 19:49:08 +00:00
arc4random_uniform.c libkern: Add arc4random_uniform 2020-05-23 17:51:06 +00:00
arc4random.c arc4random(9): Integrate with RANDOM_FENESTRASX push-reseed 2020-10-10 21:48:06 +00:00
ashldi3.c
ashrdi3.c
asprintf.c
bcd.c
bcmp.c Use __builtin for various mem* and b* (e.g. bzero) routines. 2018-06-02 18:03:35 +00:00
bcopy.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
bsearch.c
cmpdi2.c
divdi3.c
explicit_bzero.c
ffs.c
ffsl.c
ffsll.c
fls.c
flsl.c
flsll.c
fnmatch.c
gsb_crc32.c arm64: check for CRC32 support via HWCAP 2020-09-08 15:39:19 +00:00
iconv_converter_if.m
iconv_ucs.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
iconv_xlat16.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
iconv_xlat.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
iconv.c Mark more nodes as CTLFLAG_MPSAFE or CTLFLAG_NEEDGIANT (17 of many) 2020-02-26 14:26:36 +00:00
inet_aton.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
inet_ntoa.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
inet_ntop.c
inet_pton.c Remove pre-FreeBSD 7.0 compatibility. 2019-07-19 18:38:47 +00:00
jenkins_hash.c
lshrdi3.c
mcount.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
memcchr.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
memchr.c
memcmp.c Use __builtin for various mem* and b* (e.g. bzero) routines. 2018-06-02 18:03:35 +00:00
memmem.c
memset.c Use __builtin for various mem* and b* (e.g. bzero) routines. 2018-06-02 18:03:35 +00:00
moddi3.c
murmur3_32.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
qdivrem.c
qsort_r.c
qsort.c
quad.h
random.c Add prng(9) API 2020-08-13 20:48:14 +00:00
scanc.c
strcasecmp.c
strcasestr.c libkern/strcasestr.c: Drop xlocale support and connect to build. 2021-01-08 02:18:42 +03:00
strcat.c
strchr.c str(r)chr: Replace union abuse with __DECONST 2018-06-04 18:47:14 +00:00
strchrnul.c libkern: Implement strchrnul(3) 2019-08-19 22:53:05 +00:00
strcmp.c Port the NetBSD KCSAN runtime to FreeBSD. 2019-11-21 11:22:08 +00:00
strcpy.c Port the NetBSD KCSAN runtime to FreeBSD. 2019-11-21 11:22:08 +00:00
strcspn.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
strdup.c Add non-sleepable strdup variant strdup_flags 2019-02-20 20:48:10 +00:00
strlcat.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
strlcpy.c Sync strlcpy with userland version, again 2018-06-21 17:35:13 +00:00
strlen.c Reimplement strlen 2021-01-29 23:48:26 +00:00
strncat.c libkern: use nul for terminating char rather than 0 2018-02-13 19:17:48 +00:00
strncmp.c
strncpy.c libkern: use nul for terminating char rather than 0 2018-02-13 19:17:48 +00:00
strndup.c
strnlen.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
strrchr.c str(r)chr: Replace union abuse with __DECONST 2018-06-04 18:47:14 +00:00
strsep.c libkern: use nul for terminating char rather than 0 2018-02-13 19:17:48 +00:00
strspn.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
strstr.c libkern: use nul for terminating char rather than 0 2018-02-13 19:17:48 +00:00
strtol.c
strtoq.c
strtoul.c
strtouq.c
strvalid.c sys/kern: adoption of SPDX licensing ID tags. 2017-11-27 15:20:12 +00:00
timingsafe_bcmp.c
ucmpdi2.c libkern: clean up empty lines in .c and .h files 2020-09-01 21:25:23 +00:00
udivdi3.c
umoddi3.c