8a0edc914f
Add prng(9) as a replacement for random(9) in the kernel.
There are two major differences from random(9) and random(3):
- General prng(9) APIs (prng32(9), etc) do not guarantee an
implementation or particular sequence; they should not be used for
repeatable simulations.
- However, specific named API families are also exposed (for now: PCG),
and those are expected to be repeatable (when so-guaranteed by the named
algorithm).
Some minor differences from random(3) and earlier random(9):
- PRNG state for the general prng(9) APIs is per-CPU; this eliminates
contention on PRNG state in SMP workloads. Each PCPU generator in an
SMP system produces a unique sequence.
- Better statistical properties than the Park-Miller ("minstd") PRNG
(longer period, uniform distribution in all bits, passes
BigCrush/PractRand analysis).
- Faster than Park-Miller ("minstd") PRNG -- no division is required to
step PCG-family PRNGs.
For now, random(9) becomes a thin shim around prng32(). Eventually I
would like to mechanically switch consumers over to the explicit API.
Reviewed by: kib, markj (previous version both)
Discussed with: markm
Differential Revision: https://reviews.freebsd.org/D25916
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| .. | ||
| arm | ||
| arm64 | ||
| x86 | ||
| arc4random_uniform.c | ||
| arc4random.c | ||
| ashldi3.c | ||
| ashrdi3.c | ||
| asprintf.c | ||
| bcd.c | ||
| bcmp.c | ||
| bcopy.c | ||
| 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 | ||
| iconv_converter_if.m | ||
| iconv_ucs.c | ||
| iconv_xlat16.c | ||
| iconv_xlat.c | ||
| iconv.c | ||
| inet_aton.c | ||
| inet_ntoa.c | ||
| inet_ntop.c | ||
| inet_pton.c | ||
| jenkins_hash.c | ||
| lshrdi3.c | ||
| mcount.c | ||
| memcchr.c | ||
| memchr.c | ||
| memcmp.c | ||
| memmem.c | ||
| memset.c | ||
| moddi3.c | ||
| murmur3_32.c | ||
| qdivrem.c | ||
| qsort_r.c | ||
| qsort.c | ||
| quad.h | ||
| random.c | ||
| scanc.c | ||
| strcasecmp.c | ||
| strcat.c | ||
| strchr.c | ||
| strchrnul.c | ||
| strcmp.c | ||
| strcpy.c | ||
| strcspn.c | ||
| strdup.c | ||
| strlcat.c | ||
| strlcpy.c | ||
| strlen.c | ||
| strncat.c | ||
| strncmp.c | ||
| strncpy.c | ||
| strndup.c | ||
| strnlen.c | ||
| strrchr.c | ||
| strsep.c | ||
| strspn.c | ||
| strstr.c | ||
| strtol.c | ||
| strtoq.c | ||
| strtoul.c | ||
| strtouq.c | ||
| strvalid.c | ||
| timingsafe_bcmp.c | ||
| ucmpdi2.c | ||
| udivdi3.c | ||
| umoddi3.c | ||