Make parallel tests bind to different GPU.

paddle/scripts/docker/test.sh

+#!/bin/bash
+set -e
+
+# the number of process to run tests
+NUM_PROC=6
+
+# calculate and set the memory usage for each process
+MEM_USAGE=$(printf "%.2f" `echo "scale=5; 1.0 / $NUM_PROC" | bc`)
+export FLAGS_fraction_of_gpu_memory_to_use=$MEM_USAGE
+
+# get the CUDA device count
+CUDA_DEVICE_COUNT=$(nvidia-smi -L | wc -l)
+
+for (( i = 0; i < $NUM_PROC; i++ )); do
+    cuda_list=()
+    for (( j = 0; j < $CUDA_DEVICE_COUNT; j++ )); do
+        s=$[i+j]
+        n=$[s%CUDA_DEVICE_COUNT]
+        if [ $j -eq 0 ]; then
+            cuda_list=("$n")
+        else
+            cuda_list="$cuda_list,$n"
+        fi
+    done
+    echo $cuda_list
+    # CUDA_VISIBLE_DEVICES http://acceleware.com/blog/cudavisibledevices-masking-gpus
+    # ctest -I https://cmake.org/cmake/help/v3.0/manual/ctest.1.html?highlight=ctest
+    env CUDA_VISIBLE_DEVICES=$cuda_list ctest -I $i,,$NUM_PROC --output-on-failure &
+done
+wait