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vm: remove unrolled card scan loop since it appears to be a performance loss

db4
Slava Pestov 2009-10-09 02:05:31 -05:00
parent d34c7854cd
commit f6d4551da5
2 changed files with 11 additions and 22 deletions
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26
vm/copying_collector.hpp
View File

@ -46,7 +46,7 @@ struct copying_collector : collector<TargetGeneration,Policy> {
bool trace_card(SourceGeneration *gen, card *ptr, Unmarker unmarker)
{
cell card_start = this->myvm->card_to_addr(ptr);
cell card_scan = card_start + gen->card_offset(card_start);
cell card_scan = card_start + gen->first_object_in_card(card_start);
cell card_end = this->myvm->card_to_addr(ptr + 1);
bool result = this->trace_objects_between(gen,card_scan,&card_end);
@ -63,23 +63,10 @@ struct copying_collector : collector<TargetGeneration,Policy> {
card *first_card = this->myvm->deck_to_card(deck);
card *last_card = this->myvm->deck_to_card(deck + 1);
u32 *quad_ptr;
u32 quad_mask = mask | (mask << 8) | (mask << 16) | (mask << 24);
bool copied = false;
for(quad_ptr = (u32 *)first_card; quad_ptr < (u32 *)last_card; quad_ptr++)
{
if(*quad_ptr & quad_mask)
{
card *ptr = (card *)quad_ptr;
if(ptr[0] & mask) copied |= trace_card(gen,&ptr[0],unmarker);
if(ptr[1] & mask) copied |= trace_card(gen,&ptr[1],unmarker);
if(ptr[2] & mask) copied |= trace_card(gen,&ptr[2],unmarker);
if(ptr[3] & mask) copied |= trace_card(gen,&ptr[3],unmarker);
}
}
for(card *ptr = first_card; ptr < last_card; ptr++)
if(*ptr & mask) copied |= trace_card(gen,ptr,unmarker);
this->myvm->gc_stats.decks_scanned++;
@ -87,7 +74,7 @@ struct copying_collector : collector<TargetGeneration,Policy> {
}
template<typename SourceGeneration, typename Unmarker>
void trace_cards(SourceGeneration *gen, cell mask, Unmarker unmarker)
void trace_cards(SourceGeneration *gen, card mask, Unmarker unmarker)
{
u64 start = current_micros();
@ -95,10 +82,7 @@ struct copying_collector : collector<TargetGeneration,Policy> {
card_deck *last_deck = this->myvm->addr_to_deck(gen->end);
for(card_deck *ptr = first_deck; ptr < last_deck; ptr++)
{
if(*ptr & mask)
unmarker(trace_card_deck(gen,ptr,mask,unmarker),ptr);
}
if(*ptr & mask) unmarker(trace_card_deck(gen,ptr,mask,unmarker),ptr);
this->myvm->gc_stats.card_scan_time += (current_micros() - start);
}

7
vm/old_space.hpp
View File

@ -1,6 +1,11 @@
namespace factor
{
struct allot_marker {
char first_object_start;
char last_object_start;
};
struct old_space : zone {
card *allot_markers;
card *allot_markers_end;
@ -8,7 +13,7 @@ struct old_space : zone {
old_space(cell size_, cell start_);
~old_space();
cell card_offset(cell address)
cell first_object_in_card(cell address)
{
return allot_markers[(address - start) >> card_bits];
}