Cause:
use mmdetection’s tools/benchmark An error occurs when py calculates FPS
the error contents are as follows:

Traceback (most recent call last):
  File "tools/analysis_tools/benchmark.py", line 191, in <module>
    main()
  File "tools/analysis_tools/benchmark.py", line 183, in main
    init_dist(args.launcher, **cfg.dist_params)
  File "D:\Anaconda\envs\eagermot\lib\site-packages\mmcv\runner\dist_utils.py", line 18, in init_dist
    _init_dist_pytorch(backend, **kwargs)
  File "D:\Anaconda\envs\eagermot\lib\site-packages\mmcv\runner\dist_utils.py", line 32, in _init_dist_pytorch
    dist.init_process_group(backend=backend, **kwargs)
  File "D:\Anaconda\envs\eagermot\lib\site-packages\torch\distributed\distributed_c10d.py", line 510, in init_process_group
    timeout=timeout))
  File "D:\Anaconda\envs\eagermot\lib\site-packages\torch\distributed\distributed_c10d.py", line 597, in _new_process_group_helper
    raise RuntimeError("Distributed package doesn't have NCCL "
RuntimeError: Distributed package doesn't have NCCL built in

Cause analysis:
Windows does not support nccl backend

Solution:
1. Locate the following code location

File "D:\Anaconda\envs\eagermot\lib\site-packages\mmcv\runner\dist_utils.py", line 32, in _init_dist_pytorch

2. Add code before 1 (line 32)

backend='gloo'