[PATCH] D115019: ThreadPool: grow the pool only as needed

[Mehdi AMINI via Phabricator via llvm-commits]

mehdi_amini added a comment.

> particularly as the ThreadPool is created even with -mlir-disable-threading.

I'm fairly sure I fixed this one or two months ago, at least the C++ API allows to setup a project without starting a ThreadPool at all. This was a bottleneck in TensorFlow for some small MLIR work we're doing there.

There might be some similar plumbing we could do in how we handle `--mlir-disable-threading` with `mlir-opt` as well, since it is a testing tool we haven't tried to "optimize" this kind of things (you're making a good case for it though!).

That said, I like this change to lazily create thread as we go: so that even in cases where I want parallelism, I won't create more threads than actually needed!



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Comment at: llvm/lib/Support/ThreadPool.cpp:27
+    return;
+  }
+  if (ActiveThreads + Tasks.size() <= Threads.size()) {
----------------
Nit: remove trivial braces


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  https://reviews.llvm.org/D115019/new/

https://reviews.llvm.org/D115019