aboutsummaryrefslogtreecommitdiff
path: root/sysdeps/loongarch/dl-get-cpu-features.c
AgeCommit message (Collapse)Author
2023-09-21Revert "LoongArch: Add glibc.cpu.hwcap support."caiyinyu
This reverts commit a53451559dc9cce765ea5bcbb92c4007e058e92b.
2023-09-19LoongArch: Add glibc.cpu.hwcap support.caiyinyu
Key Points: 1. On lasx & lsx platforms, We must use _dl_runtime_{profile, resolve}_{lsx, lasx} to save vector registers. 2. Via "tunables", users can choose str/mem_{lasx,lsx,unaligned} functions with `export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,...`. Note: glibc.cpu.hwcaps doesn't affect _dl_runtime_{profile, resolve}_{lsx, lasx} selection. Usage Notes: 1. Only valid inputs: LASX, LSX, UAL. Case-sensitive, comma-separated, no spaces. 2. Example: `export GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL` turns on LASX & UAL. Unmentioned features turn off. With default ifunc: lasx > lsx > unaligned > aligned > generic, effect is: lasx > unaligned > aligned > generic; lsx off. 3. Incorrect GLIBC_TUNABLES settings will show error messages. For example: On lsx platforms, you cannot enable lasx features. If you do that, you will get error messages. 4. Valid input examples: - GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX: lasx > aligned > generic. - GLIBC_TUNABLES=glibc.cpu.hwcaps=LSX,UAL: lsx > unaligned > aligned > generic. - GLIBC_TUNABLES=glibc.cpu.hwcaps=LASX,UAL,LASX,UAL,LSX,LASX,UAL: Repetitions allowed but not recommended. Results in: lasx > lsx > unaligned > aligned > generic.