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AR# 20684

CORE Generator - How do I increase/decrease heap space (memory available) for CORE Generator?


General Description: How do I increase or decrease the amount of heap space for CORE Generator?


The default system memory used by coregen is 1024Mbytes (512Mbytes on windows NT). To change the amount of memory allocated:

In CORE Generator 10.1 and later select File -> Preferences and edit the "Memory Dedicated to Java" field

In Core Generator 9.2i and earlier use the coregen -J Xmx option.

coregen -J Xmx<num>m

Examples: coregen -j Xmx1048m

coregen -J Xmx384m

coregen -J Xmx256m

Here are some typical values that you can use:

Xmx256m, Xmx384m, Xmx512m, Xmx768m, Xmx2048m, or Xmx4096m

The total of the physical memory plus the virtual memory must be greater than or equal to the command line memory setting for CORE Generator. Setting the "-mxm" option to a larger value also ties up this amount of memory for CORE Generator use during your CORE Generator session. Other applications will not be able to utilize this memory until after the CORE Generator application is terminated.

The maximum heap size is machine-dependent. Many win NT systems are not able to allocate much more than about 512Mbytes. If Coregen asks for more memory than is available on the system, then Coregen will fail to open, see (Xilinx Answer 20780).

For instructions on changing the allocated heap space for coregen 6.3i or earlier, see (Xilinx Answer 9244)

A "FATAL" error message can be caused by CORE Generator running out of memory while generating large cores (such as a DA FIR with 8 channels and 32-bit coefficients).

If the CORE Generator application is invoked to have access to more than the default system memory (which equals the physical plus the virtual memory), the core generation has a better chance of succeeding.

The actual amount of memory available to the CORE Generator application might need to be to anywhere from 512 to 1024 MB for very large DA FIR cores. Large Virtex-II cores can take up to 4096 MB.

AR# 20684
Date 12/15/2012
Status Active
Type General Article