Add Support for Utilization Control

[xihuai18]

GPU Burn
Usage: gpu-burn [OPTIONS] [TIME]

-m X Use X MB of memory.
-m N% Use N% of the available GPU memory. Default is 90%
-d Use doubles
-tc Try to use Tensor cores
-l Lists all GPUs in the system
-i N Execute only on GPU N
-c FILE Use FILE as compare kernel. Default is compare.ptx
-stts T Set timeout threshold to T seconds for using SIGTERM to abort child processes before using SIGKILL. Default is 30
-u N Set GPU utilization threshold to N%. Default is 40%
-h Show this help message

Examples:
gpu-burn -d 3600 # burns all GPUs with doubles for an hour
gpu-burn -m 50% # burns using 50% of the available GPU memory
gpu-burn -l # list GPUs
gpu-burn -i 2 # burns only GPU of index 2
gpu-burn -u 60 # sets GPU utilization threshold to 60%