RuntimeError: received 0 items of
ancdata錯誤是在dataloader加載數據時出現的錯誤,原因是pytorch多線程共享tensor是通過打開文件的方式實現的,而打開文件的數量是有限制的,通過
ulimit -a
core file size (blocks, -c) 0
data seg size (kbytes, -d) unlimited
scheduling priority (-e) 0
file size (blocks, -f) unlimited
pending signals (-i) 128088
max locked memory (kbytes, -l) 16384
max memory size (kbytes, -m) unlimited
open files (-n) 1024
pipe size (512 bytes, -p) 8
POSIX message queues (bytes, -q) 819200
real-time priority (-r) 0
stack size (kbytes, -s) 8192
cpu time (seconds, -t) unlimited
max user processes (-u) 128088
virtual memory (kbytes, -v) unlimited
file locks (-x) unlimited
可查看,當需共享的tensor超過open files限制時,即會出現該錯誤。
解決辦法有2種:
- 1、增加open files的限制數量:
不能用sudo ulimit -n命令,而需執行:
sudo sh -c "ulimit -n 65535 && exec su $LOGNAME"
- 2、修改多線程的tensor方式爲file_system(默認方式爲file_descriptor,受限於open files數量):
torch.multiprocessing.set_sharing_strategy('file_system')