queue: use the default stack size on Windows #522
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The Windows thread pool implementation is calling `_beginthreadex` with a stack size of 64 KB. This seems like a misunderstanding to me. In the pthread code, `_dispatch_mgr_root_queue_init` does call `pthread_attr_setstacksize` with a 64 KB size. However, this only applies to the pthread root queue manager, and pthread root queues are only supported on Apple platforms anyway. We can confirm that using the OS default stack size is the intended semantic by looking at the `dispatch_select` test, which expects to be able to stack-allocate a 500 KB buffer in an event handler. This test is failing on Windows because there is not enough stack space. We've also run into various related issues in Swift which only happen on Windows, and I suspect that this is just because the stack size isn't so small on other platforms.
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@swift-ci please test |
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Sep 23, 2019
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queue: use the default stack size on Windows Signed-off-by: Rokhini Prabhu <rokhinip@apple.com>
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The Windows thread pool implementation is calling
_beginthreadexwitha stack size of 64 KB. This seems like a misunderstanding to me. In the
pthread code,
_dispatch_mgr_root_queue_initdoes callpthread_attr_setstacksizewith a 64 KB size. However, this onlyapplies to the pthread root queue manager, and pthread root queues are
only supported on Apple platforms anyway.
We can confirm that using the OS default stack size is the intended
semantic by looking at the
dispatch_selecttest, which expects to beable to stack-allocate a 500 KB buffer in an event handler. This test is
failing on Windows because there is not enough stack space. We've also
run into various related issues in Swift which only happen on Windows,
and I suspect that this is just because the stack size isn't so small on
other platforms.