Request for review: 7098155: Resize young gen at full collections for UseParallelGC

[Tao Mao]

Hi Jon,

New webrev is uploaded.
http://cr.openjdk.java.net/~tamao/7098155/webrev.01/

I think it makes even more sense to guard the piece of code under 
(UseAdaptiveGenerationSizePolicyAtMajorCollection...etc.)

Thanks.
Tao

On 11/6/13 7:02 PM, Jon Masamitsu wrote:
> Tao,
>
> http://cr.openjdk.java.net/~tamao/7098155/webrev.00/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp.frames.html 
>
>
> Should this block of code
>
>  266     // Swap the survivor spaces if from_space is empty
>  267     if (UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection &&
>  268         young_gen->from_space()->is_empty()) {
>  269       young_gen->from_space()->clear(SpaceDecorator::Mangle);
>  270       young_gen->swap_spaces();
>  271     }
>
> be under the guard just below it?
>
>  273     if (UseAdaptiveSizePolicy) {
>
> http://cr.openjdk.java.net/~tamao/7098155/webrev.00/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp.frames.html 
>
>
> Same question for this block of code
>
> 2103     // Swap the survivor spaces if from_space is empty
> 2104     if (UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection &&
> 2105         young_gen->from_space()->is_empty()) {
> 2106       young_gen->from_space()->clear(SpaceDecorator::Mangle);
> 2107       young_gen->swap_spaces();
> 2108     }
>
> Jon
>
>
>
> On 9/23/2013 4:13 PM, Tao Mao wrote:
>> Hi,
>>
>> changeset:
>> https://bugs.openjdk.java.net/browse/JDK-7098155
>>
>> In order to avoid the situation for UseParallelGC described in the 
>> CR, we need to resize young gen at full collections.
>>
>> And, according to the heap configuration in young gen, we need to 
>> swap from- and to-space () after full gc in order to get the young 
>> gen correctly resized after several GC's.
>>
>> webrev:
>> http://cr.openjdk.java.net/~tamao/7098155/webrev.00/
>>
>> test:
>> - Pass JPRT tests
>>
>> - RefWorkload
>>
>> (1) ParallelGC (-XX:+UseParallelGC -XX:-UseParallelOldGC)
>>
>> baseline: -XX:-UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection
>> resize: -XX:+UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection
>>
>> ./compare results_baseline_512m results_resize_512m
>> ============================================================================== 
>>
>> results_baseline_512m:
>>   Benchmark           Samples        Mean     Stdev Geomean Weight
>>   jetstream                30      192.52      9.86
>>   scimark                  30      855.62     30.33
>>   specjbb2005              30   145844.73   4552.07
>>   specjvm98                30      568.92     10.65
>> ============================================================================== 
>>
>> results_resize_512m:
>>   Benchmark           Samples        Mean     Stdev   %Diff     P 
>> Significant
>>   jetstream                30      192.89     11.33    0.19 
>> 0.894            *
>>   scimark                  30      862.21     24.17    0.77 
>> 0.356            *
>>   specjbb2005              30   142749.53   4852.66   -2.12 
>> 0.014            *
>>   specjvm98                30      566.42      8.55   -0.44 
>> 0.320            *
>> ============================================================================== 
>>
>>   * - Not Significant: A non-zero %Diff for the mean could be noise. 
>> If the
>>       %Diff is 0, an actual difference may still exist. In either 
>> case, more
>>       samples would be needed to detect an actual difference in 
>> sample means.
>>
>> (2) ParallelOldGC (-XX:+UseParallelGC -XX:+UseParallelOldGC)
>>
>> baseline: -XX:-UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection
>> resize: -XX:+UseAdaptiveSizePolicyResizeYoungGenAtMajorCollection
>>
>> ./compare results_baseline_512m_ParallelOldGC 
>> results_resize_512m_ParallelOldGC
>> ============================================================================== 
>>
>> results_baseline_512m_ParallelOldGC:
>>   Benchmark           Samples        Mean     Stdev Geomean Weight
>>   jetstream                30      196.15      8.91
>>   scimark                  30      855.92     22.58
>>   specjbb2005              30   161857.59   2653.89
>>   specjvm98                30      554.76     11.31
>> ============================================================================== 
>>
>> results_resize_512m_ParallelOldGC:
>>   Benchmark           Samples        Mean     Stdev   %Diff     P 
>> Significant
>>   jetstream                30      195.17      6.04   -0.50 
>> 0.623            *
>>   scimark                  30      853.43     22.33   -0.29 
>> 0.669            *
>>   specjbb2005              30   161027.44   2705.23   -0.51 
>> 0.235            *
>>   specjvm98                30      560.08      9.74    0.96 
>> 0.056            *
>> ============================================================================== 
>>
>>   * - Not Significant: A non-zero %Diff for the mean could be noise. 
>> If the
>>       %Diff is 0, an actual difference may still exist. In either 
>> case, more
>>       samples would be needed to detect an actual difference in 
>> sample means.
>>
>> Thanks.
>> Tao
>