[SYCL] Fix deadlock in Scheduler on Windows #1703
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Signed-off-by: Dmitry Vodopyanov <[email protected]>
Signed-off-by: Dmitry Vodopyanov <[email protected]>
Signed-off-by: Dmitry Vodopyanov <[email protected]>
s-kanaev
suggested changes
May 18, 2020
s-kanaev
reviewed
May 18, 2020
Signed-off-by: Dmitry Vodopyanov <[email protected]>
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@dm-vodopyanov, could you resolve conflicts, please? |
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@bader conflicts resolved. |
s-kanaev
approved these changes
May 20, 2020
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There was a deadlock in Scheduler on Windows only. This deadlock happens in implementation of std::shared_timed_mutex of MSVC's C++ std library.
The deadlock on Windows happens because lock ordering is not specified in C++ spec when we do lock and lock_shared simultaneously, and lock and lock_shared both wait.
It can be fixed in 2 ways:
We can't upgrade to C++17 yet, so spinlock was implemented. It fixed the deadlock on Windows. But it creates another deadlock, this time on Linux only in implementation of lock and shared_lock in pthread. To fix this, added #ifdef _WIN32 to separate Windows and Linux parts of code.