(OpenACC) pool allocator: Specified pool size too big for this device Current file

Question

I'm getting this error every time I try to run the application though it compile well:

pool allocator: Specified pool size too big for this device

Current file: /home/marco/Desktop/tools.c function: PTC3D line: 330

This file was compiled: -ta=tesla:cc35,cc50,cc60,cc70,cc70,cc75,cc80

The strange thing is that I get this error only since I restarted the PC, while before I've never get it.

I compile with:

CC = nvc

CFLAGS = -c -acc -ta=tesla:managed:cuda11.0 -Minfo=accel -w -O3 -DTEST_CASE=3

LDFLAGS = -lm -acc -ta=tesla:managed:cuda11.0

In the code nothing has been changed so maybe it is related to the compiler. I installed a new program today and I could have touched something I shouldn't have.

Answer 1

I solved going in Software & Updates, in Additional Drivers, setting the recommended driver: NVIDIA driver meta package.

Answer 2

The message should just be a warning. The pool allocator will be by-passed and instead the CUDA Unified Memory API routines will be called directly for each allocation. You might see some performance degradation if you have a lot of small allocations since the API calls have a relatively high overhead, but shouldn't hurt functionality.

The default CUDA Unified Memory pool size is 1GB, though this is modifiable by setting the environment variable NVCOMPILER_ACC_POOL_SIZE. You might try setting the size to something smaller to see if it fixes the messages. Full details can be found at: https://docs.nvidia.com/hpc-sdk/compilers/hpc-compilers-user-guide/index.html#acc-mem-unified

Exactly why the message starting appearing is unclear, but it's most likely hardware related, or possibly a CUDA driver issue. What device and CUDA driver are you using? Has anything changed with hardware?