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8027476: Improve performance of Stringtable unlink

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8027455: Improve symbol table scan times during gc pauses

Parallelize string table and symbol table scan during remark and full GC. Some additional statistics output if the experimental flag G1TraceStringSymbolTableScrubbing is set.

Reviewed-by: mgerdin, coleenp, brutisso
This commit is contained in:
Thomas Schatzl 2014-01-20 11:47:07 +01:00
parent 92d751996e
commit 4bb3631855
8 changed files with 306 additions and 61 deletions
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50
hotspot/src/share/vm/classfile/symbolTable.hpp
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@ -86,8 +86,8 @@ private:
static bool _needs_rehashing;
// For statistics
static int symbols_removed;
static int symbols_counted;
static int _symbols_removed;
static int _symbols_counted;
Symbol* allocate_symbol(const u1* name, int len, bool c_heap, TRAPS); // Assumes no characters larger than 0x7F
@ -121,6 +121,11 @@ private:
static Arena* arena() { return _arena; } // called for statistics
static void initialize_symbols(int arena_alloc_size = 0);
static volatile int _parallel_claimed_idx;
// Release any dead symbols
static void buckets_unlink(int start_idx, int end_idx, int* processed, int* removed, size_t* memory_total);
public:
enum {
symbol_alloc_batch_size = 8,
@ -177,7 +182,14 @@ public:
unsigned int* hashValues, TRAPS);
// Release any dead symbols
static void unlink();
static void unlink() {
int processed = 0;
int removed = 0;
unlink(&processed, &removed);
}
static void unlink(int* processed, int* removed);
// Release any dead symbols, possibly parallel version
static void possibly_parallel_unlink(int* processed, int* removed);
// iterate over symbols
static void symbols_do(SymbolClosure *cl);
@ -235,6 +247,9 @@ public:
// Rehash the symbol table if it gets out of balance
static void rehash_table();
static bool needs_rehashing() { return _needs_rehashing; }
// Parallel chunked scanning
static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
static int parallel_claimed_index() { return _parallel_claimed_idx; }
};
class StringTable : public Hashtable<oop, mtSymbol> {
@ -258,7 +273,10 @@ private:
// Apply the give oop closure to the entries to the buckets
// in the range [start_idx, end_idx).
static void buckets_do(OopClosure* f, int start_idx, int end_idx);
static void buckets_oops_do(OopClosure* f, int start_idx, int end_idx);
// Unlink or apply the give oop closure to the entries to the buckets
// in the range [start_idx, end_idx).
static void buckets_unlink_or_oops_do(BoolObjectClosure* is_alive, OopClosure* f, int start_idx, int end_idx, int* processed, int* removed);
StringTable() : Hashtable<oop, mtSymbol>((int)StringTableSize,
sizeof (HashtableEntry<oop, mtSymbol>)) {}
@ -280,15 +298,28 @@ public:
// GC support
// Delete pointers to otherwise-unreachable objects.
static void unlink_or_oops_do(BoolObjectClosure* cl, OopClosure* f);
static void unlink(BoolObjectClosure* cl) {
unlink_or_oops_do(cl, NULL);
static void unlink_or_oops_do(BoolObjectClosure* cl, OopClosure* f) {
int processed = 0;
int removed = 0;
unlink_or_oops_do(cl, f, &processed, &removed);
}
static void unlink(BoolObjectClosure* cl) {
int processed = 0;
int removed = 0;
unlink_or_oops_do(cl, NULL, &processed, &removed);
}
static void unlink_or_oops_do(BoolObjectClosure* cl, OopClosure* f, int* processed, int* removed);
static void unlink(BoolObjectClosure* cl, int* processed, int* removed) {
unlink_or_oops_do(cl, NULL, processed, removed);
}
// Serially invoke "f->do_oop" on the locations of all oops in the table.
static void oops_do(OopClosure* f);
// Possibly parallel version of the above
// Possibly parallel versions of the above
static void possibly_parallel_unlink_or_oops_do(BoolObjectClosure* cl, OopClosure* f, int* processed, int* removed);
static void possibly_parallel_unlink(BoolObjectClosure* cl, int* processed, int* removed) {
possibly_parallel_unlink_or_oops_do(cl, NULL, processed, removed);
}
static void possibly_parallel_oops_do(OopClosure* f);
// Hashing algorithm, used as the hash value used by the
@ -349,5 +380,6 @@ public:
// Parallel chunked scanning
static void clear_parallel_claimed_index() { _parallel_claimed_idx = 0; }
static int parallel_claimed_index() { return _parallel_claimed_idx; }
};
#endif // SHARE_VM_CLASSFILE_SYMBOLTABLE_HPP