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Added some missing command line options to README.md

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Also updated single and multi-node examples.
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David Addison 2024-07-30 14:50:45 -07:00
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1 changed files with 9 additions and 4 deletions
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@ -24,14 +24,15 @@ NCCL tests can run on multiple processes, multiple threads, and multiple CUDA de
### Quick examples
Run on 8 GPUs (`-g 8`), scanning from 8 Bytes to 128MBytes :
Run on single node with 8 GPUs (`-g 8`), scanning from 8 Bytes to 128MBytes :
```shell
$ ./build/all_reduce_perf -b 8 -e 128M -f 2 -g 8
```
Run with MPI on 10 processes (potentially on multiple nodes) with 4 GPUs each, for a total of 40 GPUs:
Run 64 MPI processes on nodes with 8 GPUs each, for a total of 64 GPUs spread across 8 nodes :
(NB: The nccl-tests binaries must be compiled with `MPI=1` for this case)
```shell
$ mpirun -np 10 ./build/all_reduce_perf -b 8 -e 128M -f 2 -g 4
$ mpirun -np 64 -N 8 ./build/all_reduce_perf -b 8 -e 8G -f 2 -g 1
```
### Performance
@ -59,14 +60,18 @@ All tests support the same set of arguments :
* `-n,--iters <iteration count>` number of iterations. Default : 20.
* `-w,--warmup_iters <warmup iteration count>` number of warmup iterations (not timed). Default : 5.
* `-m,--agg_iters <aggregation count>` number of operations to aggregate together in each iteration. Default : 1.
* `-N,--run_cycles <cycle count>` run & print each cycle. Default : 1; 0=infinite.
* `-a,--average <0/1/2/3>` Report performance as an average across all ranks (MPI=1 only). <0=Rank0,1=Avg,2=Min,3=Max>. Default : 1.
* Test operation
* `-p,--parallel_init <0/1>` use threads to initialize NCCL in parallel. Default : 0.
* `-c,--check <check iteration count>` perform count iterations, checking correctness of results on each iteration. This can be quite slow on large numbers of GPUs. Default : 1.
* `-z,--blocking <0/1>` Make NCCL collective blocking, i.e. have CPUs wait and sync after each collective. Default : 0.
* `-G,--cudagraph <num graph launches>` Capture iterations as a CUDA graph and then replay specified number of times. Default : 0.
* `-C,--report_cputime <0/1>]` Report CPU time instead of latency. Default : 0.
* `-R,--local_register <1/0>` enable local buffer registration on send/recv buffers. Default : 0.
* `-T,--timeout <time in seconds>` timeout each test after specified number of seconds. Default : disabled.
## Copyright
NCCL tests are provided under the BSD license. All source code and accompanying documentation is copyright (c) 2016-2021, NVIDIA CORPORATION. All rights reserved.
NCCL tests are provided under the BSD license. All source code and accompanying documentation is copyright (c) 2016-2024, NVIDIA CORPORATION. All rights reserved.