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docs/execution_modes.rst

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+Milabench processes overview
+============================
+
+* milabench main process
+  * gather metrics from benchmark processes, save them to file
+  * manages the benchmarks (timeout etc...)
+
+  * if ``per_gpu`` is used, milabench will launch one process per GPU (sets ``CUDA_VISIBLE_DEVCES``)
+    * each processes log their GPU data
+    * might spawn a monitor process
+      * will init pynvml
+    * dataloader will also spawn process workers
+      * usually not using GPU
+
+  * if ``njobs`` is used, milabench will launch a single process (torchrun)
+    * torchrun in turn will spawn one process per GPU
+      * RANK 0 is used for logging
+      * RANK 0 might spawn a monitor process
+        * will init pynvml
+      * dataloader will also spawn process workers 
+        * usually not using GPU
+
+Plan
+----
+
+per_gpu
++++++++
+
+``per_gpu``: used for mono gpu benchmarks, spawn one process per gpu and run the same benchmark
+
+.. code-block:: yaml
+
+   _torchvision:
+     inherits: _defaults
+     definition: ../benchmarks/torchvision
+     group: torchvision
+     install_group: torch
+     plan:
+       method: per_gpu
+
+Milabench will essentially execute something akin to below. 
+
+.. code-block:: bash
+
+   echo "---"
+   echo "fp16"
+   echo "===="
+   time (
+     CUDA_VISIBLE_DEVICES=0 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=1 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=2 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=3 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=4 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=5 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=6 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     CUDA_VISIBLE_DEVICES=7 $SRC/milabench/benchmarks/flops/activator $BASE/venv/torch $SRC/milabench/benchmarks/flops/main.py --number 30 --repeat 90 --m 8192 --n 8192 --dtype fp16 &
+     wait
+   )
+
+njobs
++++++
+
+``njobs`` used to launch a single jobs that can see all the gpus.
+
+.. code-block:: yaml
+
+   _torchvision_ddp:
+     inherits: _defaults
+     definition: ../benchmarks/torchvision_ddp
+     group: torchvision
+     install_group: torch
+     plan:
+       method: njobs
+       n: 1
+
+Milabench will essentially execute something akin to below.
+
+.. code-block:: bash
+
+   echo "---"
+   echo "lightning-gpus"
+   echo "=============="
+   time (
+     $BASE/venv/torch/bin/benchrun --nnodes=1 --rdzv-backend=c10d --rdzv-endpoint=127.0.0.1:29400 --master-addr=127.0.0.1 --master-port=29400 --nproc-per-node=8 --no-python -- python $SRC/milabench/benchmarks/lightning/main.py --epochs 10 --num-workers 8 --loader pytorch --data $BASE/data/FakeImageNet --model resnet152 --batch-size 16 &
+     wait
+   )
+
+
+
+
+
+
+