[libc-commits] [libc] [libc][Docs] Update the GPU RPC documentation (PR #79069)

[Nick Desaulniers via libc-commits]

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@@ -11,10 +11,298 @@ Remote Procedure Calls
 Remote Procedure Call Implementation
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-Certain features from the standard C library, such as allocation or printing,
-require support from the operating system. We instead implement a remote
-procedure call (RPC) interface to allow submitting work from the GPU to a host
-server that forwards it to the host system.
+Traditionally, the C library abstracts over several functions that interface 
+with the platform's operating system through system calls. The GPU however does 
+not provide an operating system that can handle target dependent operations.
+Instead, we implemented remote procedure calls to interface with the host's 
+operating system while executing on a GPU.
+
+We implemented remote procedure calls using unified virtual memory to create a 
+shared communicate channel between the two processes. This memory is often 
+pinned memory that can be accessed asynchronously and atomically by multiple 
+processes simultaneously. This supports means that we can simply provide mutual 
+exclusion on a shared better to swap work back and forth between the host system 
+and the GPU. We can then use this to create a simple client-server protocol 
+using this shared memory.
+
+This work treats the GPU as a client and the host as a server. The client 
+initiates a communication while the server listens for them. In order to 
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nickdesaulniers wrote:

s/them/requests/

https://github.com/llvm/llvm-project/pull/79069