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authorAdhemerval Zanella <azanella@linux.vnet.ibm.com>2017-12-11 17:39:42 -0200
committerTulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>2017-12-11 17:39:42 -0200
commitc9cd7b0ce5c52a3dac7347084651d7df0b39a6d0 (patch)
tree725d9e24e8a3c66866e2b8963928d4857f09b561 /sysdeps/powerpc/dl-procinfo.c
parente70c6fee466d26af36a38270e451cbe3273a6660 (diff)
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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 'sysdeps/powerpc/dl-procinfo.c')
-rw-r--r--sysdeps/powerpc/dl-procinfo.c16
1 files changed, 16 insertions, 0 deletions
diff --git a/sysdeps/powerpc/dl-procinfo.c b/sysdeps/powerpc/dl-procinfo.c
index 55a6e78aa8..c8b14454dc 100644
--- a/sysdeps/powerpc/dl-procinfo.c
+++ b/sysdeps/powerpc/dl-procinfo.c
@@ -42,6 +42,22 @@
 # define PROCINFO_CLASS
 #endif
 
+#if !IS_IN (ldconfig)
+# if !defined PROCINFO_DECL && defined SHARED
+  ._dl_powerpc_cpu_features
+# else
+PROCINFO_CLASS struct cpu_features _dl_powerpc_cpu_features
+# endif
+# ifndef PROCINFO_DECL
+= { }
+# endif
+# if !defined SHARED || defined PROCINFO_DECL
+;
+# else
+,
+# endif
+#endif
+
 #if !defined PROCINFO_DECL && defined SHARED
   ._dl_powerpc_cap_flags
 #else