Improved Profile() inference timing

[glenn-jocher]

🛠️ PR Summary

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🌟 Summary

Implemented a more accurate and granular profiling system in YOLOv5.

📊 Key Changes

• Replaced simple timing with Profile class instances for timing blocks.
• Amended code to use context management (with Profile():) for precise measurements.
• Introduced Profile class to handle timing with automatic CUDA synchronization if necessary.
• Accumulated profiling time over the course of the program.
• Removed explicit calls to time_sync() function in favor of Profile class.

🎯 Purpose & Impact

• 📈 Enhanced Profiling Accuracy: With Profile, there's fine-grained timing which should lead to better optimization decisions.
• 💡 Clearer Code Intent: Replacing ad-hoc timing with a context manager clarifies the intent and scope of code being timed.
• 💾 Easier Maintenance: Centralized timing logic within Profile makes future updates to profiling easier and less error-prone.
• 🚀 Potential Performance Improvements: Accurate profiling could guide optimization, potentially leading to performance gains for end-users.