Question about mem_stats

[seanshpark]

Jerry build with -mem_stats shows heap usage information like below.

|-- Opcode: assignment (position 348) --
| Allocated heap bytes:  24076 -> 24076 (   +0, local     0, peak 52298)
|-- End of execution of opcode assignment (position 348) --

Question is, what does the second line numbers mean?
Current iotjs for nuttx has settings of heap size 60KB and at this point gets "out of memory error" and program terminates.

[seanshpark]

At the top of the output there's a comment.

Entering block = beginning execution of initial (global) scope or function.

Information on each value is formatted as following: (p -> n ( [+-]c, local l, peak g), where:
  p     - value just before starting of item's execution;
  n     - value just after end of item's execution;
  [+-c] - difference between n and p;
  l     - temporary usage of memory during item's execution;
  g     - global peak of the value during program's execution.

Chunks are items allocated in a pool. If there is no pool with a free chunk upon chunk allocation request,
then new pool is allocated on the heap (that causes increase of number of allocated heap bytes).

[seanshpark]

@egavrin , allocated heap (the numbers) doesn't seem to climb to heap limit but mem_heap_alloc_block_try_give_memory_back() fails with "out of memory". can you guess what can be the reason? it happens while parser is working.

[ruben-ayrapetyan]

@seanshpark, could you, please, provide steps to reproduce the issue?

[seanshpark]

Thank you for looking into this issue. steps are like this;

1. get iot.js and build with default settings, refer to page https://github.com/Samsung/iotjs/wiki/Build-for-Linux

cd iotjs
./tools/build.py

2. Add memory limit to linux, in jerry-core/CMakeLists.txt

cd deps/jerry/src/jerry-core

add this

 math(EXPR MEM_HEAP_AREA_SIZE_60K "60 * 1024")
  # Linux
   set(DEFINES_JERRY_LINUX CONFIG_MEM_HEAP_AREA_SIZE=${MEM_HEAP_AREA_SIZE_60K})

3. build again

cd iotjs
./tools/build.py --noinit-submodule

4. run test program

cd test
../build/(path to iotjs executable)/iotjs hello.js

[seanshpark]

As question is solved and @ruben-ayrapetyan has checked, we can close this issue.