[libcxx-commits] [PATCH] D150284: [libc++][PSTL] Add a simple std::thread backend

[Eric Fiselier via Phabricator via libcxx-commits]

EricWF requested changes to this revision.
EricWF added inline comments.
This revision now requires changes to proceed.


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Comment at: libcxx/include/__algorithm/pstl_backends/cpu_backends/thread.h:32
+    auto __max_thread_count = thread::hardware_concurrency();
+    return __max_thread_count == 0 ? 1 : __max_thread_count;
+  }());
----------------
philnik wrote:
> EricWF wrote:
> > This calculation seems a bit weird to me.
> > 
> > We're basically saying that if no concurrency is reported, then we'll use 2 (not one) threads.
> > Why are we not just running the algorithm in the current thread in this case?
> > 
> > 
> > Either way, it seems like we should be using the calling thread to do some work rather than just waiting on the other threads to join.
> > 
> Frankly, I don't really care. As I already said, this is a shitty backend and shouldn't be used in production. This is more of a placeholder than anything else. We should implement a proper thread pool later and not instantiate threads every time an algorithm is called. 
OK, then I don't know that we should commit this.

What's the purpose of doing it poorly now, rather than properly later?



Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D150284/new/

https://reviews.llvm.org/D150284