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aarch64: Disable using DC ZVA in emag memset

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* sysdeps/aarch64/multiarch/memset_base64.S (DC_ZVA_THRESHOLD):
    Disable DC ZVA code if this macro is defined as zero.
    * sysdeps/aarch64/multiarch/memset_emag.S (DC_ZVA_THRESHOLD):
    Change to zero to disable using DC ZVA.
This commit is contained in:
Feng Xue 2019-08-14 10:48:05 +08:00
parent c3ce62cc0b
commit b68fabfbbc
3 changed files with 24 additions and 7 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2019-08-14 Feng Xue <fxue@os.amperecomputing.com>
* sysdeps/aarch64/multiarch/memset_base64.S (DC_ZVA_THRESHOLD):
Disable DC ZVA code if this macro is defined as zero.
* sysdeps/aarch64/multiarch/memset_emag.S (DC_ZVA_THRESHOLD):
Change to zero to disable using DC ZVA.
2019-08-13 Joseph Myers <joseph@codesourcery.com>
* bits/libc-header-start.h (__GLIBC_USE_IEC_60559_FUNCS_EXT):

12
sysdeps/aarch64/multiarch/memset_base64.S
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@ -23,6 +23,7 @@
# define MEMSET __memset_base64
#endif
/* To disable DC ZVA, set this threshold to 0. */
#ifndef DC_ZVA_THRESHOLD
# define DC_ZVA_THRESHOLD 512
#endif
@ -91,11 +92,12 @@ L(set96):
.p2align 4
L(set_long):
stp val, val, [dstin]
bic dst, dstin, 15
#if DC_ZVA_THRESHOLD
cmp count, DC_ZVA_THRESHOLD
ccmp val, 0, 0, cs
bic dst, dstin, 15
b.eq L(zva_64)
#endif
/* Small-size or non-zero memset does not use DC ZVA. */
sub count, dstend, dst
@ -105,7 +107,11 @@ L(set_long):
* count is less than 33 bytes, so as to bypass 2 unneccesary stps.
*/
sub count, count, 64+16+1
#if DC_ZVA_THRESHOLD
/* Align loop on 16-byte boundary, this might be friendly to i-cache. */
nop
#endif
1: stp val, val, [dst, 16]
stp val, val, [dst, 32]
@ -121,6 +127,7 @@ L(set_long):
stp val, val, [dstend, -16]
ret
#if DC_ZVA_THRESHOLD
.p2align 3
L(zva_64):
stp val, val, [dst, 16]
@ -173,6 +180,7 @@ L(zva_64):
1: stp val, val, [dstend, -32]
stp val, val, [dstend, -16]
ret
#endif
END (MEMSET)
libc_hidden_builtin_def (MEMSET)

12
sysdeps/aarch64/multiarch/memset_emag.S
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@ -21,12 +21,14 @@
# define MEMSET __memset_emag
/*
* Using dc zva to zero memory does not produce better performance if
* Using DC ZVA to zero memory does not produce better performance if
* memory size is not very large, especially when there are multiple
* processes/threads contending memory/cache. Here we use a somewhat
* large threshold to trigger usage of dc zva.
*/
# define DC_ZVA_THRESHOLD 1024
* processes/threads contending memory/cache. Here we set threshold to
* zero to disable using DC ZVA, which is good for multi-process/thread
* workloads.
*/
# define DC_ZVA_THRESHOLD 0
# include "./memset_base64.S"
#endif