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7079329: Adjust allocation prefetching for T4

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On T4 2 BIS instructions should be issued to prefetch 64 bytes

Reviewed-by: iveresov, phh, twisti
This commit is contained in:
Vladimir Kozlov 2011-08-16 16:59:46 -07:00
parent 080f790edc
commit 90651b2666
18 changed files with 299 additions and 129 deletions
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74
hotspot/src/cpu/sparc/vm/vm_version_sparc.cpp
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@ -44,20 +44,31 @@ void VM_Version::initialize() {
PrefetchScanIntervalInBytes = prefetch_scan_interval_in_bytes();
PrefetchFieldsAhead = prefetch_fields_ahead();
assert(0 <= AllocatePrefetchInstr && AllocatePrefetchInstr <= 1, "invalid value");
if( AllocatePrefetchInstr < 0 ) AllocatePrefetchInstr = 0;
if( AllocatePrefetchInstr > 1 ) AllocatePrefetchInstr = 0;
// Allocation prefetch settings
intx cache_line_size = L1_data_cache_line_size();
intx cache_line_size = prefetch_data_size();
if( cache_line_size > AllocatePrefetchStepSize )
AllocatePrefetchStepSize = cache_line_size;
if( FLAG_IS_DEFAULT(AllocatePrefetchLines) )
AllocatePrefetchLines = 3; // Optimistic value
assert( AllocatePrefetchLines > 0, "invalid value");
if( AllocatePrefetchLines < 1 ) // set valid value in product VM
AllocatePrefetchLines = 1; // Conservative value
assert(AllocatePrefetchLines > 0, "invalid value");
if( AllocatePrefetchLines < 1 ) // set valid value in product VM
AllocatePrefetchLines = 3;
assert(AllocateInstancePrefetchLines > 0, "invalid value");
if( AllocateInstancePrefetchLines < 1 ) // set valid value in product VM
AllocateInstancePrefetchLines = 1;
AllocatePrefetchDistance = allocate_prefetch_distance();
AllocatePrefetchStyle = allocate_prefetch_style();
assert(AllocatePrefetchDistance % AllocatePrefetchStepSize == 0, "invalid value");
assert((AllocatePrefetchDistance % AllocatePrefetchStepSize) == 0 &&
(AllocatePrefetchDistance > 0), "invalid value");
if ((AllocatePrefetchDistance % AllocatePrefetchStepSize) != 0 ||
(AllocatePrefetchDistance <= 0)) {
AllocatePrefetchDistance = AllocatePrefetchStepSize;
}
if (AllocatePrefetchStyle == 3 && !has_blk_init()) {
warning("BIS instructions are not available on this CPU");
@ -66,7 +77,7 @@ void VM_Version::initialize() {
UseSSE = 0; // Only on x86 and x64
_supports_cx8 = has_v9();
_supports_cx8 = has_v9();
if (is_niagara()) {
// Indirect branch is the same cost as direct
@ -99,19 +110,42 @@ void VM_Version::initialize() {
FLAG_SET_DEFAULT(InteriorEntryAlignment, 4);
}
if (is_niagara_plus()) {
if (has_blk_init() && AllocatePrefetchStyle > 0 &&
FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
// Use BIS instruction for allocation prefetch.
FLAG_SET_DEFAULT(AllocatePrefetchStyle, 3);
if (has_blk_init() && UseTLAB &&
FLAG_IS_DEFAULT(AllocatePrefetchInstr)) {
// Use BIS instruction for TLAB allocation prefetch.
FLAG_SET_ERGO(intx, AllocatePrefetchInstr, 1);
if (FLAG_IS_DEFAULT(AllocatePrefetchStyle)) {
FLAG_SET_ERGO(intx, AllocatePrefetchStyle, 3);
}
if (FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
// Use smaller prefetch distance on N2 with BIS
// Use smaller prefetch distance with BIS
FLAG_SET_DEFAULT(AllocatePrefetchDistance, 64);
}
}
if (is_T4()) {
// Double number of prefetched cache lines on T4
// since L2 cache line size is smaller (32 bytes).
if (FLAG_IS_DEFAULT(AllocatePrefetchLines)) {
FLAG_SET_ERGO(intx, AllocatePrefetchLines, AllocatePrefetchLines*2);
}
if (FLAG_IS_DEFAULT(AllocateInstancePrefetchLines)) {
FLAG_SET_ERGO(intx, AllocateInstancePrefetchLines, AllocateInstancePrefetchLines*2);
}
}
if (AllocatePrefetchStyle != 3 && FLAG_IS_DEFAULT(AllocatePrefetchDistance)) {
// Use different prefetch distance without BIS
FLAG_SET_DEFAULT(AllocatePrefetchDistance, 256);
}
if (AllocatePrefetchInstr == 1) {
// Need a space at the end of TLAB for BIS since it
// will fault when accessing memory outside of heap.
// +1 for rounding up to next cache line, +1 to be safe
int lines = AllocatePrefetchLines + 2;
int step_size = AllocatePrefetchStepSize;
int distance = AllocatePrefetchDistance;
_reserve_for_allocation_prefetch = (distance + step_size*lines)/(int)HeapWordSize;
}
}
#endif
}
@ -185,14 +219,20 @@ void VM_Version::initialize() {
#ifndef PRODUCT
if (PrintMiscellaneous && Verbose) {
tty->print("Allocation: ");
tty->print("Allocation");
if (AllocatePrefetchStyle <= 0) {
tty->print_cr("no prefetching");
tty->print_cr(": no prefetching");
} else {
tty->print(" prefetching: ");
if (AllocatePrefetchInstr == 0) {
tty->print("PREFETCH");
} else if (AllocatePrefetchInstr == 1) {
tty->print("BIS");
}
if (AllocatePrefetchLines > 1) {
tty->print_cr("PREFETCH %d, %d lines of size %d bytes", AllocatePrefetchDistance, AllocatePrefetchLines, AllocatePrefetchStepSize);
tty->print_cr(" at distance %d, %d lines of %d bytes", AllocatePrefetchDistance, AllocatePrefetchLines, AllocatePrefetchStepSize);
} else {
tty->print_cr("PREFETCH %d, one line", AllocatePrefetchDistance);
tty->print_cr(" at distance %d, one line of %d bytes", AllocatePrefetchDistance, AllocatePrefetchStepSize);
}
}
if (PrefetchCopyIntervalInBytes > 0) {