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

[Jon Masamitsu]

Changes look good.

On 11/13/2013 10:48 AM, Tao Mao wrote:
> 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.)
Agreed.  I didn't mean to imply any differently.

Jon

>
> 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
>>