[zero] optimize the optimizer step time

[Gy-Lu]

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closed #4220

📝 What does this PR do?

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Use fp16/bf16 for step comm.
Optimize the step time.

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• I have performed a self-review of my code
• I have added thorough tests.
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[github-actions]

The code coverage for the changed files is 87%.

Click me to view the complete report

Name                                                            Stmts   Miss  Cover
-----------------------------------------------------------------------------------
colossalai/booster/booster.py                                      64     10    84%
colossalai/booster/plugin/gemini_plugin.py                        110      9    92%
colossalai/booster/plugin/low_level_zero_plugin.py                125     10    92%
colossalai/booster/plugin/plugin_base.py                           40     10    75%
colossalai/booster/plugin/torch_ddp_plugin.py                      66      2    97%
colossalai/booster/plugin/torch_fsdp_plugin.py                     97     13    87%
colossalai/zero/low_level/_utils.py                               119     66    45%
colossalai/zero/low_level/bookkeeping/bucket_store.py              51      0   100%
colossalai/zero/low_level/bookkeeping/gradient_store.py            31      1    97%
colossalai/zero/low_level/bookkeeping/parameter_store.py           16      0   100%
colossalai/zero/low_level/low_level_optim.py                      313     20    94%
tests/test_booster/test_plugin/test_low_level_zero_plugin.py       59      6    90%
tests/test_checkpoint_io/test_low_level_zero_checkpoint_io.py      46      1    98%
tests/test_zero/test_low_level/test_grad_acc.py                    92     31    66%
tests/test_zero/test_low_level/test_zero1_2.py                    102      1    99%
tests/test_zero/test_low_level/test_zero_ckpt.py                   69      5    93%
tests/test_zero/test_low_level/test_zero_init.py                   40      4    90%
tests/test_zero/test_low_level/test_zero_tp.py                     66      1    98%
-----------------------------------------------------------------------------------
TOTAL                                                            1506    190    87%

[github-actions]

The code coverage for the changed files is 87%.

Click me to view the complete report

Name                                                            Stmts   Miss  Cover
-----------------------------------------------------------------------------------
colossalai/booster/booster.py                                      64     10    84%
colossalai/booster/plugin/gemini_plugin.py                        110      9    92%
colossalai/booster/plugin/low_level_zero_plugin.py                125     10    92%
colossalai/booster/plugin/plugin_base.py                           40     10    75%
colossalai/booster/plugin/torch_ddp_plugin.py                      66      2    97%
colossalai/booster/plugin/torch_fsdp_plugin.py                     97     13    87%
colossalai/zero/low_level/_utils.py                               119     66    45%
colossalai/zero/low_level/bookkeeping/bucket_store.py              51      0   100%
colossalai/zero/low_level/bookkeeping/gradient_store.py            31      1    97%
colossalai/zero/low_level/bookkeeping/parameter_store.py           16      0   100%
colossalai/zero/low_level/low_level_optim.py                      312     20    94%
tests/test_booster/test_plugin/test_low_level_zero_plugin.py       59      6    90%
tests/test_checkpoint_io/test_low_level_zero_checkpoint_io.py      46      1    98%
tests/test_zero/test_low_level/test_grad_acc.py                    92     31    66%
tests/test_zero/test_low_level/test_zero1_2.py                    102      1    99%
tests/test_zero/test_low_level/test_zero_ckpt.py                   69      5    93%
tests/test_zero/test_low_level/test_zero_init.py                   40      4    90%
tests/test_zero/test_low_level/test_zero_tp.py                     66      1    98%
-----------------------------------------------------------------------------------
TOTAL                                                            1505    190    87%