public:gsoc:takehome

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cfsmp3
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cfsmp3
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 You can still opt for the standard ones (such as fixing issues on GitHub) — these are just alternatives that are available. You can still opt for the standard ones (such as fixing issues on GitHub) — these are just alternatives that are available.
- 
-==== Interprocess communication (low-level) ==== 
-Language: **Modern C** (not C++).\\ 
-Must work in: **Linux**\\ 
- 
-Create a program, in C, that utilizes queues and memory-based interprocess communication. 
- 
-We're writing a system that encodes video using hardware encoders, specifically nVidia GPUs. 
-These consumer-grade GPUs are limited to two simultaneous encode sessions. However they can encode (really) fast, easily at 300 frames per seconds. 
- 
-We want to overcome this limitation by distributing the load in software. 
-Suppose you have 10 cameras each of them providing a never ending stream of video at 30 frames per second. 
-The job is to come up with a good plan (and proof of concept) that maximizes GPU usage. 
- 
-Here's a few things that will help you: 
- 
-  * You will need to have a queuing system that take the frames. Let's assume on the assumption that there is one process that reads data from one specific camera, so if there's 10 camera there are 10 such processes. They are the producers. Let's call them CameraManagers. 
-  * Because of the way video encoding works (in which one frame can be compressed a lot by using information from the previous one), you can 't just merge data from all the cameras and them send to the GPU as they arrive. Instead, you will need to batch them and send a number of frames from one specific camera (maybe 2 seconds, so 60 frames) at a time. We'll call the program that manages the work queue and the GPU the GPU manager. 
-  * Remember that while you do this the frames will continue to arrive. 
-  * Frames are big, so you want to minimize copying data around. For this, you have shared memory between processes. 
-  * A possibility here is to have one GPUManager, that will take the frames from the the CameraManagers. The GPUManager will need to keep one list of pending frames per camera and a queue of cameras. When a camera has sent 60 frames its list of pending frames is ready to be encoded. The GPUManager then encodes those frames (that causes a file to be generated with the output, but that's not needed for this exercise) and clears the list. Remember that while encoding was in progress other frames may have arrived and you don't want to lose them. 
-  * As mentioned, there's 2 encode sessions. The GPUManager needs to support that and simultaneously encode two frame-queues at a time. 
-  * Cameras can be added, removed, and come down (for example, they can break, or their CameraMananger can crash). You system needs to be tolerant to this. 
-  * You need to create the mockup CameraManager and the Mockup GPUManager. Since you don't have cameras of course, for each frame read a block of 1280x800 bytes from /dev/urandom.\\ 
-  * Demostrate that it works will by validating the output, for example using a checksum of each input frame and writing it to the output which can be a sample text file that contains the "camera number", "frame number", and "checksum" for that frame, in order. 
  
 ==== Meetup auto-RVSP ==== ==== Meetup auto-RVSP ====
  • public/gsoc/takehome.txt
  • Last modified: 2021/03/14 23:45
  • by cfsmp3