RFR (M): (7u60): Backport of 8027476: Improve performance of Stringtable unlink, 8027455: Improve symbol table scan times during gc pauses

[Jon Masamitsu]

Thomas,

Changes look good.

Please run some simple test (does enough work to
exercise your changes) with -XX:+UseDynamicNumberOfGCThreads .

If there is a problem (I don't expect one but would like it run),
please create a CR and assign it to me.

Thanks.

Jon

On 1/29/2014 8:09 AM, Thomas Schatzl wrote:
> Hi Mikael,
>
> On Tue, 2014-01-28 at 15:00 +0100, Mikael Gerdin wrote:
>> Thomas,
>>
>> On Tuesday 28 January 2014 11.57.33 Thomas Schatzl wrote:
>>> Hi,
>>>
>>>    I got the link for the new webrev wrong, taking two from the original
>>>> These differences are contained in symbolTable.?pp, the rest is
>>>> verbatim backport iirc.
>>>>
>>>> New webrev:
>>>> http://cr.openjdk.java.net/~tschatzl/8027476/webrev
>>> Correct webrev is at:
>>>
>>> http://cr.openjdk.java.net/~tschatzl/8027476.7u60/webrev
>> symbolTable.cpp:
>>
>>   103       Symbol* s = entry->literal();
>>   104       memory_total += s->object_size(); << should be (*memory_total) +=
>>   105       (*processed)++;
>>
>> g1ColletedHeap.cpp:
>>
>> 5237     guarantee(StringTable::parallel_claimed_index() >=
>> _initial_string_table_size,
>> 5238               err_msg("claim value "INT32_FORMAT" after unlink less than
>> initial string table size "INT32_FORMAT,
>> 5239                       StringTable::parallel_claimed_index(),
>> _initial_string_table_size));
>> 5240     guarantee(!_process_strings || SymbolTable::parallel_claimed_index()
>>> = _initial_symbol_table_size,
>> 5241               err_msg("claim value "INT32_FORMAT" after unlink less than
>> initial symbol table size "INT32_FORMAT,
>> 5242                       SymbolTable::parallel_claimed_index(),
>> _initial_symbol_table_size));
>> 5243
>>
>> You've removed the !_process_strings from the guarantee compared to 9.
>> Also, I noticed that the 9 versions has !_process_strings in both guarantees
>> although I think the second one should be !_process_symbols.
> All fixed in the new webrev at
> http://cr.openjdk.java.net/~tschatzl/8027476.7u60/webrev.1/
>
> Thanks a lot.
>
> I will file a bug for 8u20 and 9.
>
> Thanks,
>    Thomas
>