From 7e8e54e84c63171e748bbf09516fd517e6821ace Mon Sep 17 00:00:00 2001
From: Gustaf Rydholm <gustaf.rydholm@gmail.com>
Date: Sat, 20 Mar 2021 18:09:06 +0100
Subject: Inital commit for refactoring to lightning

---
 training/gpu_manager.py | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 training/gpu_manager.py

(limited to 'training/gpu_manager.py')

diff --git a/training/gpu_manager.py b/training/gpu_manager.py
new file mode 100644
index 0000000..ce1b3dd
--- /dev/null
+++ b/training/gpu_manager.py
@@ -0,0 +1,62 @@
+"""GPUManager class."""
+import os
+import time
+from typing import Optional
+
+import gpustat
+from loguru import logger
+import numpy as np
+from redlock import Redlock
+
+
+GPU_LOCK_TIMEOUT = 5000  # ms
+
+
+class GPUManager:
+    """Class for allocating GPUs."""
+
+    def __init__(self, verbose: bool = False) -> None:
+        """Initializes Redlock manager."""
+        self.lock_manager = Redlock([{"host": "localhost", "port": 6379, "db": 0}])
+        self.verbose = verbose
+
+    def get_free_gpu(self) -> int:
+        """Gets a free GPU.
+
+        If some GPUs are available, try reserving one by checking out an exclusive redis lock.
+        If none available or can not get lock, sleep and check again.
+
+        Returns:
+            int: The gpu index.
+
+        """
+        while True:
+            gpu_index = self._get_free_gpu()
+            if gpu_index is not None:
+                return gpu_index
+
+            if self.verbose:
+                logger.debug(f"pid {os.getpid()} sleeping")
+            time.sleep(GPU_LOCK_TIMEOUT / 1000)
+
+    def _get_free_gpu(self) -> Optional[int]:
+        """Fetches an available GPU index."""
+        try:
+            available_gpu_indices = [
+                gpu.index
+                for gpu in gpustat.GPUStatCollection.new_query()
+                if gpu.memory_used < 0.5 * gpu.memory_total
+            ]
+        except Exception as e:
+            logger.debug(f"Got the following exception: {e}")
+            return None
+
+        if available_gpu_indices:
+            gpu_index = np.random.choice(available_gpu_indices)
+            if self.verbose:
+                logger.debug(f"pid {os.getpid()} picking gpu {gpu_index}")
+            if self.lock_manager.lock(f"gpu_{gpu_index}", GPU_LOCK_TIMEOUT):
+                return int(gpu_index)
+            if self.verbose:
+                logger.debug(f"pid {os.getpid()} could not get lock.")
+        return None
-- 
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