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Combined approach.

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This combines some ideas from these two CLs:
    - try stosd/w
    - update memset16/32 inlining heuristics

BUG=skia:4316

Blinking in and out for perf.skia.org.
TBR=reed@google.com

Review URL: https://codereview.chromium.org/1356133002
This commit is contained in:
mtklein 2015-09-21 10:50:56 -07:00 committed by Commit bot
parent 4ae26258ef
commit 46243a7c02
1 changed files with 29 additions and 13 deletions
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42
include/core/SkUtils.h
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@ -9,6 +9,27 @@
#define SkUtils_DEFINED
#include "SkTypes.h"
#if defined(SK_BUILD_FOR_WIN)
#include <intrin.h>
#endif
#if defined(SK_CPU_X86)
static inline void rep_stosw(uint16_t buffer[], uint16_t value, int count) {
#if defined(SK_BUILD_FOR_WIN)
__stosw(buffer, value, count);
#else
__asm__ __volatile__ ( "rep stosw" : "+D"(buffer), "+c"(count) : "a"(value) );
#endif
}
static inline void rep_stosd(uint32_t buffer[], uint32_t value, int count) {
#if defined(SK_BUILD_FOR_WIN)
__stosd((PDWORD)buffer, value, count);
#else
__asm__ __volatile__ ( "rep stosl" : "+D"(buffer), "+c"(count) : "a"(value) );
#endif
}
#endif
namespace SkOpts {
extern void (*memset16)(uint16_t[], uint16_t, int);
@ -17,13 +38,8 @@ namespace SkOpts {
///////////////////////////////////////////////////////////////////////////////
// The inlining heuristics below were determined using bench/MemsetBench.cpp
// on a x86 desktop, a Nexus 7 with and without NEON, and a Nexus 9:
// - on x86, inlining was never faster,
// - on ARMv7, inlining was faster for N<=10. Putting this check inside the NEON
// code was not helpful; it's got to be here outside.
// - NEON code generation for ARMv8 with GCC 4.9 is terrible,
// making the NEON code ~8x slower that just a serial loop.
// The stosw/d and inlining heuristics below were determined using
// bench/MemsetBench.cpp and perf.skia.org.
/** Similar to memset(), but it assigns a 16bit value into the buffer.
@param buffer The memory to have value copied into it
@ -31,10 +47,10 @@ namespace SkOpts {
@param count The number of times value should be copied into the buffer.
*/
static inline void sk_memset16(uint16_t buffer[], uint16_t value, int count) {
#if defined(SK_CPU_ARM64)
#if defined(SK_CPU_X86)
if (count > 30) { rep_stosw(buffer, value, count); return; }
#elif defined(SK_ARM_HAS_NEON)
while (count --> 0) { *buffer++ = value; } return;
#elif defined(SK_CPU_ARM32)
if (count <= 10) { while (count --> 0) { *buffer++ = value; } return; }
#endif
SkOpts::memset16(buffer, value, count);
}
@ -45,10 +61,10 @@ static inline void sk_memset16(uint16_t buffer[], uint16_t value, int count) {
@param count The number of times value should be copied into the buffer.
*/
static inline void sk_memset32(uint32_t buffer[], uint32_t value, int count) {
#if defined(SK_CPU_ARM64)
#if defined(SK_CPU_X86)
if (count > 30) { rep_stosd(buffer, value, count); return; }
#elif defined(SK_ARM_HAS_NEON)
while (count --> 0) { *buffer++ = value; } return;
#elif defined(SK_CPU_ARM32)
if (count <= 10) { while (count --> 0) { *buffer++ = value; } return; }
#endif
SkOpts::memset32(buffer, value, count);
}