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8149365: aarch64: memory copy does not prefetch on backwards copy

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Implement prefetch on backwards copies

Reviewed-by: aph
This commit is contained in:
Ed Nevill 2016-02-08 14:14:35 +00:00
parent eaaec5b879
commit 4c5566f502
2 changed files with 19 additions and 3 deletions
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13
hotspot/src/cpu/aarch64/vm/stubGenerator_aarch64.cpp
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@ -786,6 +786,7 @@ class StubGenerator: public StubCodeGenerator {
int offset;
const Register t0 = r3, t1 = r4, t2 = r5, t3 = r6,
t4 = r7, t5 = r10, t6 = r11, t7 = r12;
const Register stride = r13;
assert_different_registers(rscratch1, t0, t1, t2, t3, t4, t5, t6, t7);
assert_different_registers(s, d, count, rscratch1);
@ -845,10 +846,18 @@ class StubGenerator: public StubCodeGenerator {
__ ldp(t4, t5, Address(s, 6 * unit));
__ ldp(t6, t7, Address(__ pre(s, 8 * unit)));
int prefetch = PrefetchCopyIntervalInBytes;
bool use_stride = false;
if (direction == copy_backwards) {
use_stride = prefetch > 256;
prefetch = -prefetch;
if (use_stride) __ mov(stride, prefetch);
}
__ bind(again);
if (direction == copy_forwards && PrefetchCopyIntervalInBytes > 0)
__ prfm(Address(s, PrefetchCopyIntervalInBytes), PLDL1KEEP);
if (PrefetchCopyIntervalInBytes > 0)
__ prfm(use_stride ? Address(s, stride) : Address(s, prefetch), PLDL1KEEP);
__ stp(t0, t1, Address(d, 2 * unit));
__ ldp(t0, t1, Address(s, 2 * unit));

9
hotspot/src/cpu/aarch64/vm/vm_version_aarch64.cpp
View File

@ -120,7 +120,14 @@ void VM_Version::get_processor_features() {
FLAG_SET_DEFAULT(AllocatePrefetchStepSize, 64);
FLAG_SET_DEFAULT(PrefetchScanIntervalInBytes, 256);
FLAG_SET_DEFAULT(PrefetchFieldsAhead, 256);
FLAG_SET_DEFAULT(PrefetchCopyIntervalInBytes, 256);
if (FLAG_IS_DEFAULT(PrefetchCopyIntervalInBytes))
FLAG_SET_DEFAULT(PrefetchCopyIntervalInBytes, 256);
if ((PrefetchCopyIntervalInBytes & 7) || (PrefetchCopyIntervalInBytes >= 32768)) {
warning("PrefetchCopyIntervalInBytes must be a multiple of 8 and < 32768");
PrefetchCopyIntervalInBytes &= ~7;
if (PrefetchCopyIntervalInBytes >= 32768)
PrefetchCopyIntervalInBytes = 32760;
}
unsigned long auxv = getauxval(AT_HWCAP);