From 0c5feaf9d967f340e05f21f701bb7b7e3a9ec476 Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Sun, 6 Dec 2020 20:43:10 +0800
Subject: [PATCH 1/8] add engine for unified entrypoints in downstream projects

---
 mmcv/__init__.py           |   1 +
 mmcv/engine/__init__.py    |   9 ++
 mmcv/engine/test.py        | 131 ++++++++++++++++++++
 mmcv/engine/train.py       |   0
 mmcv/engine/utils.py       | 246 +++++++++++++++++++++++++++++++++++++
 mmcv/runner/base_runner.py |   5 +-
 6 files changed, 390 insertions(+), 2 deletions(-)
 create mode 100644 mmcv/engine/__init__.py
 create mode 100644 mmcv/engine/test.py
 create mode 100644 mmcv/engine/train.py
 create mode 100644 mmcv/engine/utils.py

diff --git a/mmcv/__init__.py b/mmcv/__init__.py
index 74ee0442fc..c33cfe3c3f 100644
--- a/mmcv/__init__.py
+++ b/mmcv/__init__.py
@@ -1,6 +1,7 @@
 # Copyright (c) Open-MMLab. All rights reserved.
 # flake8: noqa
 from .arraymisc import *
+from .engine import *
 from .fileio import *
 from .image import *
 from .utils import *
diff --git a/mmcv/engine/__init__.py b/mmcv/engine/__init__.py
new file mode 100644
index 0000000000..5cb9529e0e
--- /dev/null
+++ b/mmcv/engine/__init__.py
@@ -0,0 +1,9 @@
+from .test import collect_results_cpu, collect_results_gpu, multi_gpu_test
+from .utils import (default_args_parser, gather_info, set_random_seed,
+                    setup_cfg, setup_envs, setup_logger)
+
+__all__ = [
+    'default_args_parser', 'gather_info', 'setup_cfg', 'setup_envs',
+    'setup_logger', 'multi_gpu_test', 'collect_results_gpu',
+    'collect_results_cpu', 'set_random_seed'
+]
diff --git a/mmcv/engine/test.py b/mmcv/engine/test.py
new file mode 100644
index 0000000000..86f79aa3c9
--- /dev/null
+++ b/mmcv/engine/test.py
@@ -0,0 +1,131 @@
+import os.path as osp
+import pickle
+import shutil
+import tempfile
+import time
+
+import torch
+import torch.distributed as dist
+
+import mmcv
+from mmcv.runner import get_dist_info
+
+
+def multi_gpu_test(model, data_loader, tmpdir=None, gpu_collect=False):
+    """Test model with multiple gpus.
+
+    This method tests model with multiple gpus and collects the results
+    under two different modes: gpu and cpu modes. By setting 'gpu_collect=True'
+    it encodes results to gpu tensors and use gpu communication for results
+    collection. On cpu mode it saves the results on different gpus to 'tmpdir'
+    and collects them by the rank 0 worker.
+
+    Args:
+        model (nn.Module): Model to be tested.
+        data_loader (nn.Dataloader): Pytorch data loader.
+        tmpdir (str): Path of directory to save the temporary results from
+            different gpus under cpu mode.
+        gpu_collect (bool): Option to use either gpu or cpu to collect results.
+
+    Returns:
+        list: The prediction results.
+    """
+    model.eval()
+    results = []
+    dataset = data_loader.dataset
+    rank, world_size = get_dist_info()
+    if rank == 0:
+        prog_bar = mmcv.ProgressBar(len(dataset))
+    time.sleep(2)  # This line can prevent deadlock problem in some cases.
+    for i, data in enumerate(data_loader):
+        with torch.no_grad():
+            result = model(return_loss=False, rescale=True, **data)
+        results.extend(result)
+
+        if rank == 0:
+            batch_size = len(result)
+            for _ in range(batch_size * world_size):
+                prog_bar.update()
+
+    # collect results from all ranks
+    if gpu_collect:
+        results = collect_results_gpu(results, len(dataset))
+    else:
+        results = collect_results_cpu(results, len(dataset), tmpdir)
+    return results
+
+
+def collect_results_cpu(result_part, size, tmpdir=None):
+    rank, world_size = get_dist_info()
+    # create a tmp dir if it is not specified
+    if tmpdir is None:
+        MAX_LEN = 512
+        # 32 is whitespace
+        dir_tensor = torch.full((MAX_LEN, ),
+                                32,
+                                dtype=torch.uint8,
+                                device='cuda')
+        if rank == 0:
+            mmcv.mkdir_or_exist('.dist_test')
+            tmpdir = tempfile.mkdtemp(dir='.dist_test')
+            tmpdir = torch.tensor(
+                bytearray(tmpdir.encode()), dtype=torch.uint8, device='cuda')
+            dir_tensor[:len(tmpdir)] = tmpdir
+        dist.broadcast(dir_tensor, 0)
+        tmpdir = dir_tensor.cpu().numpy().tobytes().decode().rstrip()
+    else:
+        mmcv.mkdir_or_exist(tmpdir)
+    # dump the part result to the dir
+    mmcv.dump(result_part, osp.join(tmpdir, f'part_{rank}.pkl'))
+    dist.barrier()
+    # collect all parts
+    if rank != 0:
+        return None
+    else:
+        # load results of all parts from tmp dir
+        part_list = []
+        for i in range(world_size):
+            part_file = osp.join(tmpdir, f'part_{i}.pkl')
+            part_list.append(mmcv.load(part_file))
+        # sort the results
+        ordered_results = []
+        for res in zip(*part_list):
+            ordered_results.extend(list(res))
+        # the dataloader may pad some samples
+        ordered_results = ordered_results[:size]
+        # remove tmp dir
+        shutil.rmtree(tmpdir)
+        return ordered_results
+
+
+def collect_results_gpu(result_part, size):
+    rank, world_size = get_dist_info()
+    # dump result part to tensor with pickle
+    part_tensor = torch.tensor(
+        bytearray(pickle.dumps(result_part)), dtype=torch.uint8, device='cuda')
+    # gather all result part tensor shape
+    shape_tensor = torch.tensor(part_tensor.shape, device='cuda')
+    shape_list = [shape_tensor.clone() for _ in range(world_size)]
+    dist.all_gather(shape_list, shape_tensor)
+    # padding result part tensor to max length
+    shape_max = torch.tensor(shape_list).max()
+    part_send = torch.zeros(shape_max, dtype=torch.uint8, device='cuda')
+    part_send[:shape_tensor[0]] = part_tensor
+    part_recv_list = [
+        part_tensor.new_zeros(shape_max) for _ in range(world_size)
+    ]
+    # gather all result part
+    dist.all_gather(part_recv_list, part_send)
+
+    if rank == 0:
+        part_list = []
+        for recv, shape in zip(part_recv_list, shape_list):
+            part_list.append(
+                pickle.loads(recv[:shape[0]].cpu().numpy().tobytes()))
+        # sort the results
+        ordered_results = []
+        for res in zip(*part_list):
+            ordered_results.extend(list(res))
+        # the dataloader may pad some samples
+        ordered_results = ordered_results[:size]
+        return ordered_results
diff --git a/mmcv/engine/train.py b/mmcv/engine/train.py
new file mode 100644
index 0000000000..e69de29bb2
diff --git a/mmcv/engine/utils.py b/mmcv/engine/utils.py
new file mode 100644
index 0000000000..15c448a1cc
--- /dev/null
+++ b/mmcv/engine/utils.py
@@ -0,0 +1,246 @@
+import argparse
+import os
+import os.path as osp
+import random
+import time
+
+import numpy as np
+import torch
+
+from ..runner import get_dist_info, init_dist
+from ..utils import (Config, DictAction, import_modules_from_strings,
+                     mkdir_or_exist)
+
+
+def set_random_seed(seed, deterministic=False):
+    """Set random seed.
+
+    Args:
+        seed (int): Seed to be used.
+        deterministic (bool): Whether to set the deterministic option for
+            CUDNN backend, i.e., set `torch.backends.cudnn.deterministic`
+            to True and `torch.backends.cudnn.benchmark` to False.
+            Default: False.
+    """
+    random.seed(seed)
+    np.random.seed(seed)
+    torch.manual_seed(seed)
+    torch.cuda.manual_seed_all(seed)
+    if deterministic:
+        torch.backends.cudnn.deterministic = True
+        torch.backends.cudnn.benchmark = False
+
+
+def default_args_parser():
+    """Default argument parser for OpenMMLab projects.
+
+    This function is used as a default argument parser in OpenMMLab projects.
+    To add customized arguments, users can create a new parser function which
+    calls this functions first.
+
+    Returns:
+        :obj:`argparse.ArgumentParser`: Argument parser
+    """
+    parser = argparse.ArgumentParser(
+        description='OpenMMLab Default Argument Parser')
+
+    # common arguments for both training and testing
+    parser.add_argument('config', help='config file path')
+    parser.add_argument(
+        '--tmpdir',
+        help='tmp directory used for collecting results from multiple '
+        'workers, available when gpu-collect is not specified')
+    parser.add_argument(
+        '--launcher',
+        choices=['none', 'pytorch', 'slurm', 'mpi'],
+        default='none',
+        help='job launcher')
+    parser.add_argument('--local_rank', type=int, default=0)
+    parser.add_argument(
+        '--gpu-collect',
+        action='store_true',
+        help='whether to use gpu to collect results in multi-gpu testing.')
+
+    # common arguments for training
+    parser.add_argument('--work-dir', help='the dir to save logs and models')
+    parser.add_argument(
+        '--resume-from', help='the checkpoint file to resume from')
+    parser.add_argument(
+        '--no-validate',
+        action='store_true',
+        help='whether not to evaluate the checkpoint during training')
+    group_gpus = parser.add_mutually_exclusive_group()
+    group_gpus.add_argument(
+        '--gpus',
+        type=int,
+        help='number of gpus to use '
+        '(only applicable to non-distributed training)')
+    group_gpus.add_argument(
+        '--gpu-ids',
+        type=int,
+        nargs='+',
+        help='ids of gpus to use '
+        '(only applicable to non-distributed training)')
+    parser.add_argument('--seed', type=int, default=None, help='random seed')
+    parser.add_argument(
+        '--deterministic',
+        action='store_true',
+        help='whether to set deterministic options for CUDNN backend.')
+    parser.add_argument(
+        '--cfg-options',
+        nargs='+',
+        action=DictAction,
+        help='override some settings in the used config, the key-value pair '
+        'in xxx=yyy format will be merged into config file.')
+
+    # common arguments for testing
+    parser.add_argument('checkpoint', help='checkpoint file')
+    parser.add_argument('--out', help='output result file in pickle format')
+    parser.add_argument(
+        '--fuse-conv-bn',
+        action='store_true',
+        help='Whether to fuse conv and bn, this will slightly increase'
+        'the inference speed')
+    parser.add_argument(
+        '--format-only',
+        action='store_true',
+        help='Format the output results without perform evaluation. It is'
+        'useful when you want to format the result to a specific format and '
+        'submit it to the test server')
+    parser.add_argument(
+        '--eval',
+        type=str,
+        nargs='+',
+        help='evaluation metrics, which depends on the dataset, e.g., "bbox",'
+        ' "segm", "proposal" for COCO, and "mAP", "recall" for PASCAL VOC')
+    parser.add_argument('--show', action='store_true', help='show results')
+    parser.add_argument(
+        '--show-dir', help='directory where painted images will be saved')
+    parser.add_argument(
+        '--show-score-thr',
+        type=float,
+        default=0.3,
+        help='score threshold (default: 0.3)')
+    # TODO: decide whether to maintain two place for modifing eval options
+    parser.add_argument(
+        '--eval-options',
+        nargs='+',
+        action=DictAction,
+        help='custom options for evaluation, the key-value pair in xxx=yyy '
+        'format will be kwargs for dataset.evaluate() function')
+
+    return parser
+
+
+def setup_cfg(args):
+    """Set up config.
+
+    Arguments:
+        args (:obj:`argparse.ArgumentParser`): arguments from entry point
+
+    Returns:
+        Config: config dict
+    """
+    cfg = Config.fromfile(args.config)
+    # merge config from args.cfg_options
+    if args.cfg_options is not None:
+        cfg.merge_from_dict(args.cfg_options)
+
+    # work_dir is determined in this priority: CLI > segment in file > filename
+    if args.work_dir is not None:
+        # update configs according to CLI args if args.work_dir is not None
+        cfg.work_dir = args.work_dir
+    elif cfg.get('work_dir', None) is None:
+        # use config filename as default work_dir if cfg.work_dir is None
+        cfg.work_dir = osp.join('./work_dirs',
+                                osp.splitext(osp.basename(args.config))[0])
+    if args.resume_from is not None:
+        cfg.resume_from = args.resume_from
+    if args.gpu_ids is not None:
+        cfg.gpu_ids = args.gpu_ids
+    else:
+        cfg.gpu_ids = range(1) if args.gpus is None else range(args.gpus)
+
+    import_modules_from_strings(**cfg.get('custom_imports', []))
+    return Config
+
+
+def setup_envs(cfg, args):
+    """Setup running environments.
+
+    This function initialize the running environment.
+    It does the following things in order:
+
+        1. Set local rank in the environment
+        2. Set cudnn benchmark
+        3. Initialize distributed function
+        4. Create work dir anddump config file
+        5. Set random seed
+
+    Args:
+        cfg (:obj:`Config`): [description]
+        args (:obj:``): [description]
+    """
+    # set local rank
+    if 'LOCAL_RANK' not in os.environ:
+        os.environ['LOCAL_RANK'] = str(args.local_rank)
+
+    # set cudnn_benchmark
+    torch.backends.cudnn.benchmark = cfg.get('cudnn_benchmark', False)
+
+    # init distributed env first, since logger depends on the dist info.
+    if args.launcher == 'none':
+        distributed = False
+    else:
+        distributed = True
+        init_dist(args.launcher, **cfg.dist_params)
+        # re-set gpu_ids with distributed training mode
+        _, world_size = get_dist_info()
+        cfg.gpu_ids = range(world_size)
+
+    # create work_dir
+    mkdir_or_exist(osp.abspath(cfg.work_dir))
+    # dump config
+    cfg.dump(osp.join(cfg.work_dir, osp.basename(args.config)))
+
+    # set random seeds
+    if args.seed is not None:
+        set_random_seed(args.seed, deterministic=args.deterministic)
+    cfg.seed = args.seed
+    return distributed
+
+
+def setup_logger(cfg, get_root_logger):
+    timestamp = time.strftime('%Y%m%d_%H%M%S', time.localtime())
+    log_file = osp.join(cfg.work_dir, f'{timestamp}.log')
+    get_root_logger(log_file=log_file, log_level=cfg.log_level)
+    return timestamp
+
+
+def gather_info(cfg, args, distributed, get_root_logger, collect_env):
+    """
+    1. collect & log env info
+    2. collect exp name, config
+    """
+    # init the meta dict to record some important information such as
+    # environment info and seed, which will be logged
+    meta = dict()
+    # log env info
+    env_info_dict = collect_env()
+    env_info = '\n'.join([(f'{k}: {v}') for k, v in env_info_dict.items()])
+    dash_line = '-' * 60 + '\n'
+    meta['env_info'] = env_info
+    meta['config'] = cfg.pretty_text
+    meta['seed'] = args.seed
+    meta['exp_name'] = osp.basename(args.config)
+
+    # log some basic info
+    logger = get_root_logger()
+    logger.info('Environment info:\n' + dash_line + env_info + '\n' +
+                dash_line)
+    logger.info(f'Set random seed to {args.seed}, '
+                f'deterministic: {args.deterministic}')
+    logger.info(f'Distributed training: {distributed}')
+    logger.info(f'Config:\n{cfg.pretty_text}')
+
+    return meta
diff --git a/mmcv/runner/base_runner.py b/mmcv/runner/base_runner.py
index 82cb76a868..70c5e4e364 100644
--- a/mmcv/runner/base_runner.py
+++ b/mmcv/runner/base_runner.py
@@ -55,7 +55,8 @@ def __init__(self,
                  logger=None,
                  meta=None,
                  max_iters=None,
-                 max_epochs=None):
+                 max_epochs=None,
+                 timestamp=None):
         if batch_processor is not None:
             if not callable(batch_processor):
                 raise TypeError('batch_processor must be callable, '
@@ -119,7 +120,7 @@ def __init__(self,
             self._model_name = self.model.__class__.__name__
 
         self._rank, self._world_size = get_dist_info()
-        self.timestamp = get_time_str()
+        self.timestamp = timestamp if timestamp is not None else get_time_str()
         self.mode = None
         self._hooks = []
         self._epoch = 0

From 49fd931f6605bbb7195a1162b4f4874842036d11 Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Sun, 6 Dec 2020 21:06:42 +0800
Subject: [PATCH 2/8] add multi_gpu_test back to packages

---
 mmcv/engine/utils.py | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/mmcv/engine/utils.py b/mmcv/engine/utils.py
index 15c448a1cc..81107275ee 100644
--- a/mmcv/engine/utils.py
+++ b/mmcv/engine/utils.py
@@ -94,7 +94,10 @@ def default_args_parser():
         'in xxx=yyy format will be merged into config file.')
 
     # common arguments for testing
-    parser.add_argument('checkpoint', help='checkpoint file')
+    parser.add_argument(
+        '--test-only', action='store_true', help='whether to perform evaluate')
+    parser.add_argument(
+        '--checkpoint', help='checkpoint file used in evaluation')
     parser.add_argument('--out', help='output result file in pickle format')
     parser.add_argument(
         '--fuse-conv-bn',
@@ -161,8 +164,9 @@ def setup_cfg(args):
     else:
         cfg.gpu_ids = range(1) if args.gpus is None else range(args.gpus)
 
-    import_modules_from_strings(**cfg.get('custom_imports', []))
-    return Config
+    if cfg.get('custom_imports', None):
+        import_modules_from_strings(**cfg['custom_imports'])
+    return cfg
 
 
 def setup_envs(cfg, args):

From 3ece1c3b195af7332f4849f72d6eb485399b92cb Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Sun, 20 Dec 2020 21:12:35 +0800
Subject: [PATCH 3/8] Refactor engine utils

---
 mmcv/engine/__init__.py         |   6 +-
 mmcv/engine/utils.py            | 113 ++++++++++++++------------------
 mmcv/utils/config.py            |  24 ++++++-
 tests/test_engine/test_utils.py |   8 +++
 tests/test_utils/test_config.py |  15 +++++
 5 files changed, 100 insertions(+), 66 deletions(-)
 create mode 100644 tests/test_engine/test_utils.py

diff --git a/mmcv/engine/__init__.py b/mmcv/engine/__init__.py
index 5cb9529e0e..a02c4243bf 100644
--- a/mmcv/engine/__init__.py
+++ b/mmcv/engine/__init__.py
@@ -1,9 +1,9 @@
 from .test import collect_results_cpu, collect_results_gpu, multi_gpu_test
 from .utils import (default_args_parser, gather_info, set_random_seed,
-                    setup_cfg, setup_envs, setup_logger)
+                    setup_cfg, setup_envs)
 
 __all__ = [
     'default_args_parser', 'gather_info', 'setup_cfg', 'setup_envs',
-    'setup_logger', 'multi_gpu_test', 'collect_results_gpu',
-    'collect_results_cpu', 'set_random_seed'
+    'multi_gpu_test', 'collect_results_gpu', 'collect_results_cpu',
+    'set_random_seed'
 ]
diff --git a/mmcv/engine/utils.py b/mmcv/engine/utils.py
index 81107275ee..4c7d393462 100644
--- a/mmcv/engine/utils.py
+++ b/mmcv/engine/utils.py
@@ -2,7 +2,6 @@
 import os
 import os.path as osp
 import random
-import time
 
 import numpy as np
 import torch
@@ -62,9 +61,6 @@ def default_args_parser():
         help='whether to use gpu to collect results in multi-gpu testing.')
 
     # common arguments for training
-    parser.add_argument('--work-dir', help='the dir to save logs and models')
-    parser.add_argument(
-        '--resume-from', help='the checkpoint file to resume from')
     parser.add_argument(
         '--no-validate',
         action='store_true',
@@ -81,17 +77,6 @@ def default_args_parser():
         nargs='+',
         help='ids of gpus to use '
         '(only applicable to non-distributed training)')
-    parser.add_argument('--seed', type=int, default=None, help='random seed')
-    parser.add_argument(
-        '--deterministic',
-        action='store_true',
-        help='whether to set deterministic options for CUDNN backend.')
-    parser.add_argument(
-        '--cfg-options',
-        nargs='+',
-        action=DictAction,
-        help='override some settings in the used config, the key-value pair '
-        'in xxx=yyy format will be merged into config file.')
 
     # common arguments for testing
     parser.add_argument(
@@ -119,11 +104,6 @@ def default_args_parser():
     parser.add_argument('--show', action='store_true', help='show results')
     parser.add_argument(
         '--show-dir', help='directory where painted images will be saved')
-    parser.add_argument(
-        '--show-score-thr',
-        type=float,
-        default=0.3,
-        help='score threshold (default: 0.3)')
     # TODO: decide whether to maintain two place for modifing eval options
     parser.add_argument(
         '--eval-options',
@@ -135,30 +115,44 @@ def default_args_parser():
     return parser
 
 
-def setup_cfg(args):
+def setup_cfg(args, cfg_args):
     """Set up config.
 
+    Note:
+        This function assumes the arguments are parsed from the parser of
+        defined by :meth:`default_args_parser`, which contains necessary keys
+        for distributed training including 'launcher', 'local_rank', etc.
+
     Arguments:
         args (:obj:`argparse.ArgumentParser`): arguments from entry point
+        cfg_args (list[str]): list of key-value pairs that will be merged
+            into cfgs.
 
     Returns:
         Config: config dict
     """
     cfg = Config.fromfile(args.config)
     # merge config from args.cfg_options
-    if args.cfg_options is not None:
-        cfg.merge_from_dict(args.cfg_options)
-
-    # work_dir is determined in this priority: CLI > segment in file > filename
-    if args.work_dir is not None:
-        # update configs according to CLI args if args.work_dir is not None
-        cfg.work_dir = args.work_dir
-    elif cfg.get('work_dir', None) is None:
+    if len(cfg_args) > 0:
+        cfg.merge_from_list(cfg_args)
+
+    if cfg.get('work_dir', None) is None:
         # use config filename as default work_dir if cfg.work_dir is None
         cfg.work_dir = osp.join('./work_dirs',
                                 osp.splitext(osp.basename(args.config))[0])
-    if args.resume_from is not None:
-        cfg.resume_from = args.resume_from
+
+    # initialize some default but necessary options
+    cfg.seed = cfg.get('seed', None)
+    cfg.deterministic = cfg.get('deterministic', False)
+    cfg.resume_from = cfg.get('resume_from', None)
+
+    cfg.launcher = args.launcher
+    cfg.local_rank = args.local_rank
+    if args.launcher == 'none':
+        cfg.distributed = False
+    else:
+        cfg.distributed = True
+
     if args.gpu_ids is not None:
         cfg.gpu_ids = args.gpu_ids
     else:
@@ -169,7 +163,7 @@ def setup_cfg(args):
     return cfg
 
 
-def setup_envs(cfg, args):
+def setup_envs(cfg, dump_cfg=True):
     """Setup running environments.
 
     This function initialize the running environment.
@@ -182,69 +176,64 @@ def setup_envs(cfg, args):
         5. Set random seed
 
     Args:
-        cfg (:obj:`Config`): [description]
-        args (:obj:``): [description]
+        cfg (:obj:`Config`): Config object.
+        dump_cfg: Whether to dump configs.
     """
     # set local rank
     if 'LOCAL_RANK' not in os.environ:
-        os.environ['LOCAL_RANK'] = str(args.local_rank)
+        os.environ['LOCAL_RANK'] = str(cfg.local_rank)
 
     # set cudnn_benchmark
     torch.backends.cudnn.benchmark = cfg.get('cudnn_benchmark', False)
 
     # init distributed env first, since logger depends on the dist info.
-    if args.launcher == 'none':
-        distributed = False
-    else:
-        distributed = True
-        init_dist(args.launcher, **cfg.dist_params)
+    if cfg.distributed:
+        init_dist(cfg.launcher, **cfg.dist_params)
         # re-set gpu_ids with distributed training mode
         _, world_size = get_dist_info()
         cfg.gpu_ids = range(world_size)
 
     # create work_dir
     mkdir_or_exist(osp.abspath(cfg.work_dir))
-    # dump config
-    cfg.dump(osp.join(cfg.work_dir, osp.basename(args.config)))
+    if cfg.local_rank == 0 and dump_cfg:
+        # dump config
+        cfg.dump(osp.join(cfg.work_dir, osp.basename(cfg.filename)))
 
     # set random seeds
-    if args.seed is not None:
-        set_random_seed(args.seed, deterministic=args.deterministic)
-    cfg.seed = args.seed
-    return distributed
+    if cfg.seed is not None:
+        set_random_seed(cfg.seed, deterministic=cfg.deterministic)
 
 
-def setup_logger(cfg, get_root_logger):
-    timestamp = time.strftime('%Y%m%d_%H%M%S', time.localtime())
-    log_file = osp.join(cfg.work_dir, f'{timestamp}.log')
-    get_root_logger(log_file=log_file, log_level=cfg.log_level)
-    return timestamp
+def gather_info(cfg, logger, env_info_dict):
+    """Gather running information.
 
+    This function do the following things in order:
 
-def gather_info(cfg, args, distributed, get_root_logger, collect_env):
-    """
-    1. collect & log env info
-    2. collect exp name, config
+        1. collect & log env info
+        2. collect exp name, config
+
+    Args:
+        cfg (:obj:`Config`): Config object.
+        logger (:obj:`logging.logger`): Logger.
+        env_info_dict (dict): Environment information.
     """
     # init the meta dict to record some important information such as
     # environment info and seed, which will be logged
     meta = dict()
     # log env info
-    env_info_dict = collect_env()
     env_info = '\n'.join([(f'{k}: {v}') for k, v in env_info_dict.items()])
     dash_line = '-' * 60 + '\n'
     meta['env_info'] = env_info
     meta['config'] = cfg.pretty_text
-    meta['seed'] = args.seed
-    meta['exp_name'] = osp.basename(args.config)
+    meta['seed'] = cfg.seed
+    meta['exp_name'] = osp.basename(cfg.filename)
 
     # log some basic info
-    logger = get_root_logger()
     logger.info('Environment info:\n' + dash_line + env_info + '\n' +
                 dash_line)
-    logger.info(f'Set random seed to {args.seed}, '
-                f'deterministic: {args.deterministic}')
-    logger.info(f'Distributed training: {distributed}')
+    logger.info(f'Set random seed to {cfg.seed}, '
+                f'deterministic: {cfg.deterministic}')
+    logger.info(f'Distributed training: {cfg.distributed}')
     logger.info(f'Config:\n{cfg.pretty_text}')
 
     return meta
diff --git a/mmcv/utils/config.py b/mmcv/utils/config.py
index 76739c361a..1b9c617a8f 100644
--- a/mmcv/utils/config.py
+++ b/mmcv/utils/config.py
@@ -404,7 +404,7 @@ def dump(self, file=None):
                 mmcv.dump(cfg_dict, file)
 
     def merge_from_dict(self, options):
-        """Merge list into cfg_dict.
+        """Merge dict into cfg_dict.
 
         Merge the dict parsed by MultipleKVAction into this cfg.
 
@@ -434,6 +434,28 @@ def merge_from_dict(self, options):
         super(Config, self).__setattr__(
             '_cfg_dict', Config._merge_a_into_b(option_cfg_dict, cfg_dict))
 
+    def merge_from_list(self, option_list):
+        """Merge list into cfg_dict.
+
+        Merge the dict parsed by MultipleKVAction into this cfg.
+
+        Examples:
+            >>> options = {'model.backbone.depth': 50,
+            ...            'model.backbone.with_cp':True}
+            >>> cfg = Config(dict(model=dict(backbone=dict(type='ResNet'))))
+            >>> cfg.merge_from_dict(options)
+            >>> cfg_dict = super(Config, self).__getattribute__('_cfg_dict')
+            >>> assert cfg_dict == dict(
+            ...     model=dict(backbone=dict(depth=50, with_cp=True)))
+
+        Args:
+            options (dict): dict of configs to merge from.
+        """
+        assert len(option_list) % 2 == 0, '"option_list" should be specified' \
+            f'in pair , got odd length {len(option_list)}.'
+        options = {k: v for k, v in zip(option_list[0::2], option_list[1::2])}
+        self.merge_from_dict(options)
+
 
 class DictAction(Action):
     """
diff --git a/tests/test_engine/test_utils.py b/tests/test_engine/test_utils.py
new file mode 100644
index 0000000000..3b97b4c1a7
--- /dev/null
+++ b/tests/test_engine/test_utils.py
@@ -0,0 +1,8 @@
+from mmcv.engine import default_args_parser
+
+
+def test_default_args():
+    parser = default_args_parser()
+    known_args, cfg_args = parser.parse_known_args(
+        ['./configs/config.py', 'dist_params.port', '2999'])
+    assert cfg_args == ['dist_params.port', '2999']
diff --git a/tests/test_utils/test_config.py b/tests/test_utils/test_config.py
index e13daff122..bf4a139164 100644
--- a/tests/test_utils/test_config.py
+++ b/tests/test_utils/test_config.py
@@ -220,6 +220,21 @@ def test_merge_from_dict():
     assert cfg.item3 is False
 
 
+def test_merge_from_list():
+    cfg_file = osp.join(data_path, 'config/a.py')
+    cfg = Config.fromfile(cfg_file)
+    input_options = [
+        'item2.a', 1, 'item2.b', 0.1, 'item2.c', 'c', 'item3', False
+    ]
+    cfg.merge_from_list(input_options)
+    assert cfg.item2 == dict(a=1, b=0.1, c='c')
+    assert cfg.item3 is False
+
+    # test invalid option list that is in odd length
+    with pytest.raises(AssertionError):
+        cfg.merge_from_list(['item2.a', 1, 'item2.b', 0.1, 'item3'])
+
+
 def test_merge_delete():
     cfg_file = osp.join(data_path, 'config/delete.py')
     cfg = Config.fromfile(cfg_file)

From 85afd8269c0cdb619be8056ea546493b809ca4fa Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Mon, 28 Dec 2020 16:05:04 +0800
Subject: [PATCH 4/8] add unit test & command line support

---
 mmcv/engine/utils.py                 |  2 +-
 mmcv/utils/config.py                 | 69 +++++++++++++++++++---------
 tests/test_engine/test_entrypoint.py | 24 ++++++++++
 tests/test_engine/test_utils.py      | 35 +++++++++++++-
 4 files changed, 106 insertions(+), 24 deletions(-)
 create mode 100644 tests/test_engine/test_entrypoint.py

diff --git a/mmcv/engine/utils.py b/mmcv/engine/utils.py
index 4c7d393462..3ed727205c 100644
--- a/mmcv/engine/utils.py
+++ b/mmcv/engine/utils.py
@@ -134,7 +134,7 @@ def setup_cfg(args, cfg_args):
     cfg = Config.fromfile(args.config)
     # merge config from args.cfg_options
     if len(cfg_args) > 0:
-        cfg.merge_from_list(cfg_args)
+        cfg.merge_from_arg_list(cfg_args)
 
     if cfg.get('work_dir', None) is None:
         # use config filename as default work_dir if cfg.work_dir is None
diff --git a/mmcv/utils/config.py b/mmcv/utils/config.py
index 1b9c617a8f..36d75d17ba 100644
--- a/mmcv/utils/config.py
+++ b/mmcv/utils/config.py
@@ -62,6 +62,28 @@ def add_args(parser, cfg, prefix=''):
     return parser
 
 
+def parse_int_float_bool(val):
+    """Parse string value to be integer, float, or boolean value.
+
+    Args:
+        val (str): String of variable
+
+    Returns:
+        int, float, bool, str: Converted variable
+    """
+    try:
+        return int(val)
+    except ValueError:
+        pass
+    try:
+        return float(val)
+    except ValueError:
+        pass
+    if val.lower() in ['true', 'false']:
+        return True if val.lower() == 'true' else False
+    return val
+
+
 class Config:
     """A facility for config and config files.
 
@@ -434,26 +456,43 @@ def merge_from_dict(self, options):
         super(Config, self).__setattr__(
             '_cfg_dict', Config._merge_a_into_b(option_cfg_dict, cfg_dict))
 
-    def merge_from_list(self, option_list):
-        """Merge list into cfg_dict.
+    def merge_from_arg_list(self, option_list, strict=True):
+        """Merge unparsed argument list into cfg_dict.
 
         Merge the dict parsed by MultipleKVAction into this cfg.
 
         Examples:
-            >>> options = {'model.backbone.depth': 50,
-            ...            'model.backbone.with_cp':True}
+            >>> options = ['model.backbone.depth', 50,
+            ...            'model.backbone.with_cp', True]
             >>> cfg = Config(dict(model=dict(backbone=dict(type='ResNet'))))
-            >>> cfg.merge_from_dict(options)
+            >>> cfg.merge_from_args_list(options, strict=False)
             >>> cfg_dict = super(Config, self).__getattribute__('_cfg_dict')
             >>> assert cfg_dict == dict(
             ...     model=dict(backbone=dict(depth=50, with_cp=True)))
 
         Args:
-            options (dict): dict of configs to merge from.
+            option_list (list[str]): List of raw arguments to merge from.
         """
         assert len(option_list) % 2 == 0, '"option_list" should be specified' \
             f'in pair , got odd length {len(option_list)}.'
-        options = {k: v for k, v in zip(option_list[0::2], option_list[1::2])}
+
+        def arg2key(key_name):
+            if key_name.startswith('--'):
+                opt_key = key_name[2:]
+            elif strict:
+                raise ValueError('Expect argument to be start with "--"'
+                                 f'Got {key_name}')
+            else:
+                opt_key = key_name
+            return opt_key.replace('-', '_')
+
+        options = {}
+        for key, val in zip(option_list[0::2], option_list[1::2]):
+            key = arg2key(key)
+            val = [parse_int_float_bool(v) for v in val.split(',')]
+            if len(val) == 1:
+                val = val[0]
+            options[key] = val
         self.merge_from_dict(options)
 
 
@@ -464,25 +503,11 @@ class DictAction(Action):
     be passed as comma separated values, i.e KEY=V1,V2,V3
     """
 
-    @staticmethod
-    def _parse_int_float_bool(val):
-        try:
-            return int(val)
-        except ValueError:
-            pass
-        try:
-            return float(val)
-        except ValueError:
-            pass
-        if val.lower() in ['true', 'false']:
-            return True if val.lower() == 'true' else False
-        return val
-
     def __call__(self, parser, namespace, values, option_string=None):
         options = {}
         for kv in values:
             key, val = kv.split('=', maxsplit=1)
-            val = [self._parse_int_float_bool(v) for v in val.split(',')]
+            val = [parse_int_float_bool(v) for v in val.split(',')]
             if len(val) == 1:
                 val = val[0]
             options[key] = val
diff --git a/tests/test_engine/test_entrypoint.py b/tests/test_engine/test_entrypoint.py
new file mode 100644
index 0000000000..d8e6a3fc60
--- /dev/null
+++ b/tests/test_engine/test_entrypoint.py
@@ -0,0 +1,24 @@
+import os.path as osp
+import tempfile
+import time
+
+from mmcv.engine import default_args_parser, gather_info, setup_cfg, setup_envs
+from mmcv.utils import collect_env, get_logger
+
+data_path = osp.join(osp.dirname(osp.dirname(__file__)), 'data')
+
+
+def test_entrypoint():
+    with tempfile.TemporaryDirectory() as tmp_dir:
+        opts = f'{data_path}/config/a.py --work-dir {tmp_dir} --log-level INFO'
+        args, cfg_opts = default_args_parser().parse_known_args(opts.split())
+        cfg = setup_cfg(args, cfg_opts)
+
+        setup_envs(cfg)
+        timestamp = time.strftime('%Y%m%d_%H%M%S', time.localtime())
+        log_file = osp.join(cfg.work_dir, f'{timestamp}.log')
+        logger = get_logger(
+            name='mmcv', log_file=log_file, log_level=cfg.log_level)
+
+        meta = gather_info(cfg, logger, collect_env())
+        assert meta is not None
diff --git a/tests/test_engine/test_utils.py b/tests/test_engine/test_utils.py
index 3b97b4c1a7..c5589faec9 100644
--- a/tests/test_engine/test_utils.py
+++ b/tests/test_engine/test_utils.py
@@ -1,8 +1,41 @@
+import pytest
+
 from mmcv.engine import default_args_parser
+from mmcv.utils import Config
 
 
 def test_default_args():
     parser = default_args_parser()
     known_args, cfg_args = parser.parse_known_args(
-        ['./configs/config.py', 'dist_params.port', '2999'])
+        './configs/config.py dist_params.port 2999'.split())
     assert cfg_args == ['dist_params.port', '2999']
+
+    cfg = Config(dict(a=1, b=dict(b1=[0, 1])))
+
+    # test ValueError when strict=False and argument does not start
+    # with "--"
+    with pytest.raises(ValueError):
+        cfg.merge_from_arg_list(cfg_args)
+
+    cfg.merge_from_arg_list(cfg_args, strict=False)
+    assert cfg.dist_params.port == 2999
+
+    # test nargs before unknow args
+    known_args, cfg_args = parser.parse_known_args(
+        './configs/config.py --gpu-ids 1 2 3 --work-dir work_dirs'.split())
+    assert cfg_args == ['--work-dir', 'work_dirs']
+
+    cfg = Config(dict(a=1, b=dict(b1=[0, 1])))
+    cfg.merge_from_arg_list(cfg_args)
+    assert cfg.work_dir == 'work_dirs'
+
+    # test float, bool type and list
+    known_args, cfg_args = parser.parse_known_args(
+        './configs/config.py --a-b a_b --list 1,2,3.5 --bool True'.split())
+    assert cfg_args == ['--a-b', 'a_b', '--list', '1,2,3.5', '--bool', 'True']
+
+    cfg = Config(dict(a=1, b=dict(b1=[0, 1])))
+    cfg.merge_from_arg_list(cfg_args)
+    assert cfg.a_b == 'a_b'
+    assert cfg.list == [1, 2, 3.5]
+    assert cfg.bool

From 4351bf23ce4a7d2fca89b2e2b70d4e93b78af836 Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Mon, 28 Dec 2020 16:25:46 +0800
Subject: [PATCH 5/8] try pass build w/o torch

---
 .github/workflows/build.yml | 2 +-
 mmcv/__init__.py            | 1 -
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index aad4adacdb..3d52bf2d0f 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -48,7 +48,7 @@ jobs:
       - name: Run unittests and generate coverage report
         run: |
           pip install -r requirements/test.txt
-          pytest tests/ --ignore=tests/test_runner --ignore=tests/test_optimizer.py --ignore=tests/test_cnn --ignore=tests/test_parallel.py --ignore=tests/test_ops --ignore=tests/test_load_model_zoo.py --ignore=tests/test_utils/test_logging.py --ignore=tests/test_image/test_io.py --ignore=tests/test_utils/test_registry.py --ignore=tests/test_utils/test_parrots_jit.py
+          pytest tests/ --ignore=tests/test_runner --ignore=tests/test_optimizer.py --ignore=tests/test_cnn --ignore=tests/test_parallel.py --ignore=tests/test_ops --ignore=tests/test_load_model_zoo.py --ignore=tests/test_utils/test_logging.py --ignore=tests/test_image/test_io.py --ignore=tests/test_utils/test_registry.py --ignore=tests/test_utils/test_parrots_jit.py --ignore=tests/test_engine
 
   build_without_ops:
     runs-on: ubuntu-latest
diff --git a/mmcv/__init__.py b/mmcv/__init__.py
index c33cfe3c3f..74ee0442fc 100644
--- a/mmcv/__init__.py
+++ b/mmcv/__init__.py
@@ -1,7 +1,6 @@
 # Copyright (c) Open-MMLab. All rights reserved.
 # flake8: noqa
 from .arraymisc import *
-from .engine import *
 from .fileio import *
 from .image import *
 from .utils import *

From d9d7b91bcd0aa98cde945ddfc8306983ff35d57e Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Mon, 28 Dec 2020 16:51:59 +0800
Subject: [PATCH 6/8] clean unit tests

---
 tests/test_utils/test_config.py | 15 ---------------
 1 file changed, 15 deletions(-)

diff --git a/tests/test_utils/test_config.py b/tests/test_utils/test_config.py
index f207da4ef5..013bb2f5c5 100644
--- a/tests/test_utils/test_config.py
+++ b/tests/test_utils/test_config.py
@@ -238,21 +238,6 @@ def test_merge_from_dict():
         cfg.merge_from_dict(input_options, allow_list_keys=True)
 
 
-def test_merge_from_list():
-    cfg_file = osp.join(data_path, 'config/a.py')
-    cfg = Config.fromfile(cfg_file)
-    input_options = [
-        'item2.a', 1, 'item2.b', 0.1, 'item2.c', 'c', 'item3', False
-    ]
-    cfg.merge_from_list(input_options)
-    assert cfg.item2 == dict(a=1, b=0.1, c='c')
-    assert cfg.item3 is False
-
-    # test invalid option list that is in odd length
-    with pytest.raises(AssertionError):
-        cfg.merge_from_list(['item2.a', 1, 'item2.b', 0.1, 'item3'])
-
-
 def test_merge_delete():
     cfg_file = osp.join(data_path, 'config/delete.py')
     cfg = Config.fromfile(cfg_file)

From 5b1292f34b5ee8de3307d4870f9829e432c28857 Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Mon, 28 Dec 2020 21:56:31 +0800
Subject: [PATCH 7/8] fix merge bug

---
 mmcv/utils/config.py | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/mmcv/utils/config.py b/mmcv/utils/config.py
index cf63dcd154..f20d3b7ba5 100644
--- a/mmcv/utils/config.py
+++ b/mmcv/utils/config.py
@@ -95,11 +95,11 @@ def parse_iterable(val):
         list | tuple: The expanded list or tuple from the string.
 
     Examples:
-        >>> DictAction._parse_iterable('1,2,3')
+        >>> parse_iterable('1,2,3')
         [1, 2, 3]
-        >>> DictAction._parse_iterable('[a, b, c]')
+        >>> parse_iterable('[a, b, c]')
         ['a', 'b', 'c']
-        >>> DictAction._parse_iterable('[(1, 2, 3), [a, b], c]')
+        >>> parse_iterable('[(1, 2, 3), [a, b], c]')
         [(1, 2, 3), ['a', 'b], 'c']
     """
 
@@ -133,11 +133,11 @@ def find_next_comma(string):
         val = val[1:-1]
     elif ',' not in val:
         # val is a single value
-        return DictAction._parse_int_float_bool(val)
+        return parse_int_float_bool(val)
     values = []
     while len(val) > 0:
         comma_idx = find_next_comma(val)
-        element = DictAction._parse_iterable(val[:comma_idx])
+        element = parse_iterable(val[:comma_idx])
         values.append(element)
         val = val[comma_idx + 1:]
     if is_tuple:
@@ -600,9 +600,6 @@ def arg2key(key_name):
         options = {}
         for key, val in zip(option_list[0::2], option_list[1::2]):
             key = arg2key(key)
-            val = [parse_int_float_bool(v) for v in val.split(',')]
-            if len(val) == 1:
-                val = val[0]
             options[key] = parse_iterable(val)
         self.merge_from_dict(options)
 
@@ -620,8 +617,5 @@ def __call__(self, parser, namespace, values, option_string=None):
         options = {}
         for kv in values:
             key, val = kv.split('=', maxsplit=1)
-            val = [parse_int_float_bool(v) for v in val.split(',')]
-            if len(val) == 1:
-                val = val[0]
             options[key] = parse_iterable(val)
         setattr(namespace, self.dest, options)

From cd92f81215f17a3bb19a7b9469fd065212a7b0cd Mon Sep 17 00:00:00 2001
From: ZwwWayne <wayne.zw@outlook.com>
Date: Mon, 28 Dec 2020 22:24:51 +0800
Subject: [PATCH 8/8] rename

---
 tests/test_engine/{test_utils.py => test_launch_utils.py} | 0
 1 file changed, 0 insertions(+), 0 deletions(-)
 rename tests/test_engine/{test_utils.py => test_launch_utils.py} (100%)

diff --git a/tests/test_engine/test_utils.py b/tests/test_engine/test_launch_utils.py
similarity index 100%
rename from tests/test_engine/test_utils.py
rename to tests/test_engine/test_launch_utils.py