diff options
| author | Adhemerval Zanella <azanella@linux.vnet.ibm.com> | 2017-12-11 17:39:42 -0200 |
|---|---|---|
| committer | Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> | 2017-12-11 17:39:42 -0200 |
| commit | c9cd7b0ce5c52a3dac7347084651d7df0b39a6d0 (patch) | |
| tree | 725d9e24e8a3c66866e2b8963928d4857f09b561 /manual | |
| parent | e70c6fee466d26af36a38270e451cbe3273a6660 (diff) | |
powerpc: POWER8 memcpy optimization for cached memory
On POWER8, unaligned memory accesses to cached memory has little impact
on performance as opposed to its ancestors.
It is disabled by default and will only be available when the tunable
glibc.tune.cached_memopt is set to 1.
__memcpy_power8_cached __memcpy_power7
============================================================
max-size=4096: 33325.70 ( 12.65%) 38153.00
max-size=8192: 32878.20 ( 11.17%) 37012.30
max-size=16384: 33782.20 ( 11.61%) 38219.20
max-size=32768: 33296.20 ( 11.30%) 37538.30
max-size=65536: 33765.60 ( 10.53%) 37738.40
* manual/tunables.texi (Hardware Capability Tunables): Document
glibc.tune.cached_memopt.
* sysdeps/powerpc/cpu-features.c: New file.
* sysdeps/powerpc/cpu-features.h: New file.
* sysdeps/powerpc/dl-procinfo.c [!IS_IN(ldconfig)]: Add
_dl_powerpc_cpu_features.
* sysdeps/powerpc/dl-tunables.list: New file.
* sysdeps/powerpc/ldsodefs.h: Include cpu-features.h.
* sysdeps/powerpc/powerpc32/power4/multiarch/init-arch.h
(INIT_ARCH): Initialize use_aligned_memopt.
* sysdeps/powerpc/powerpc64/dl-machine.h [defined(SHARED &&
IS_IN(rtld))]: Restrict dl_platform_init availability and
initialize CPU features used by tunables.
* sysdeps/powerpc/powerpc64/multiarch/Makefile (sysdep_routines):
Add memcpy-power8-cached.
* sysdeps/powerpc/powerpc64/multiarch/ifunc-impl-list.c: Add
__memcpy_power8_cached.
* sysdeps/powerpc/powerpc64/multiarch/memcpy.c: Likewise.
* sysdeps/powerpc/powerpc64/multiarch/memcpy-power8-cached.S:
New file.
Reviewed-by: Rajalakshmi Srinivasaraghavan <raji@linux.vnet.ibm.com>
Diffstat (limited to 'manual')
| -rw-r--r-- | manual/tunables.texi | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/manual/tunables.texi b/manual/tunables.texi index e851b95c59..6e0ee28980 100644 --- a/manual/tunables.texi +++ b/manual/tunables.texi @@ -319,6 +319,16 @@ the ones in @code{sysdeps/x86/cpu-features.h}. This tunable is specific to i386 and x86-64. @end deftp +@deftp Tunable glibc.tune.cached_memopt +The @code{glibc.tune.cached_memopt=[0|1]} tunable allows the user to +enable optimizations recommended for cacheable memory. If set to +@code{1}, @theglibc{} assumes that the process memory image consists +of cacheable (non-device) memory only. The default, @code{0}, +indicates that the process may use device memory. + +This tunable is specific to powerpc, powerpc64 and powerpc64le. +@end deftp + @deftp Tunable glibc.tune.cpu The @code{glibc.tune.cpu=xxx} tunable allows the user to tell @theglibc{} to assume that the CPU is @code{xxx} where xxx may have one of these values: |