Adjust initial heap size to allow for quicker startup

[bhermann]

It was suggested to adjust the initial heap size to get better startup times for the client.

[bhermann]

@hariharansrc Could you please look into this during this week?

[hariharansrc]

Sure I will work on it.

[hariharansrc]

There is no improvement in startup time when configuring heap size

  //64 MB
./delphi test > out64  2.70s user 0.22s system 197% cpu 1.477 total

   size_t ErgoHeapSizeLimit                        = 0                                         {product} {default}
   size_t HeapSizePerGCThread                      = 43620760                                  {product} {default}
   size_t InitialHeapSize                          = 67108864                                  {product} {command line}
   size_t LargePageHeapSizeThreshold               = 134217728                                 {product} {default}
   size_t MaxHeapSize                              = 67108864                                  {product} {command line}
   size_t MinHeapSize                              = 67108864                                  {product} {command line}
    uintx NonNMethodCodeHeapSize                   = 5830732                                {pd product} {ergonomic}
    uintx NonProfiledCodeHeapSize                  = 122913754                              {pd product} {ergonomic}
    uintx ProfiledCodeHeapSize                     = 122913754                              {pd product} {ergonomic}
   size_t SoftMaxHeapSize                          = 67108864                               {manageable} {ergonomic}
 




 //128 MB
/delphi test > out128  2.81s user 0.20s system 194% cpu 1.546 total

   size_t ErgoHeapSizeLimit                        = 0                                         {product} {default}
   size_t HeapSizePerGCThread                      = 43620760                                  {product} {default}
   size_t InitialHeapSize                          = 134217728                                 {product} {command line}
   size_t LargePageHeapSizeThreshold               = 134217728                                 {product} {default}
   size_t MaxHeapSize                              = 134217728                                 {product} {command line}
   size_t MinHeapSize                              = 134217728                                 {product} {command line}
    uintx NonNMethodCodeHeapSize                   = 5830732                                {pd product} {ergonomic}
    uintx NonProfiledCodeHeapSize                  = 122913754                              {pd product} {ergonomic}
    uintx ProfiledCodeHeapSize                     = 122913754                              {pd product} {ergonomic}
   size_t SoftMaxHeapSize                          = 134217728                              {manageable} {ergonomic}
 
.

 //256 MB
./delphi test > out256  2.82s user 0.29s system 158% cpu 1.966 total

   size_t ErgoHeapSizeLimit                        = 0                                         {product} {default}
   size_t HeapSizePerGCThread                      = 43620760                                  {product} {default}
   size_t InitialHeapSize                          = 268435456                                 {product} {command line}
   size_t LargePageHeapSizeThreshold               = 134217728                                 {product} {default}
   size_t MaxHeapSize                              = 268435456                                 {product} {command line}
   size_t MinHeapSize                              = 268435456                                 {product} {command line}
    uintx NonNMethodCodeHeapSize                   = 5830732                                {pd product} {ergonomic}
    uintx NonProfiledCodeHeapSize                  = 122913754                              {pd product} {ergonomic}
    uintx ProfiledCodeHeapSize                     = 122913754                              {pd product} {ergonomic}
   size_t SoftMaxHeapSize                          = 2

[hariharansrc]

There is a 50 seconds improvement when Class Data Sharing is used.

[johannesduesing]

Closing this issue, as the experiments above show that there is no significant improvement in startup time when using a bigger heap size. While it may be possible to automate the process of Class Data Sharing, i don't think that we want to do that in our build pipeline, as it is highly platform dependant.