diff options
Diffstat (limited to 'src/core/hle/kernel/k_spin_lock.cpp')
| -rw-r--r-- | src/core/hle/kernel/k_spin_lock.cpp | 48 |
1 files changed, 45 insertions, 3 deletions
diff --git a/src/core/hle/kernel/k_spin_lock.cpp b/src/core/hle/kernel/k_spin_lock.cpp index 8525320374..107d6f1aa3 100644 --- a/src/core/hle/kernel/k_spin_lock.cpp +++ b/src/core/hle/kernel/k_spin_lock.cpp @@ -3,18 +3,60 @@ #include "core/hle/kernel/k_spin_lock.h" +#if defined(_M_X64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__) +#include <immintrin.h> +#endif + namespace Kernel { +namespace { + +// Spins of about 30-140 cycles each before a contended Lock sleeps (a few microseconds). +constexpr int SpinCount = 128; + +void Pause() { +#if defined(_M_X64) || defined(_M_IX86) || defined(__x86_64__) || defined(__i386__) + _mm_pause(); +#elif defined(__aarch64__) + asm volatile("yield"); +#endif +} + +} // Anonymous namespace + void KSpinLock::Lock() { - m_lock.lock(); + u32 expected = 0; + if (m_state.compare_exchange_strong(expected, 1, std::memory_order_acquire, + std::memory_order_relaxed)) { + return; + } + for (int spin = 0; spin < SpinCount; ++spin) { + Pause(); + if (m_state.load(std::memory_order_relaxed) == 0) { + expected = 0; + if (m_state.compare_exchange_weak(expected, 1, std::memory_order_acquire, + std::memory_order_relaxed)) { + return; + } + } + } + // Mark the lock contended and sleep until it is released; taken this way it stays marked, + // so its Unlock wakes the next sleeper. + while (m_state.exchange(2, std::memory_order_acquire) != 0) { + m_state.wait(2, std::memory_order_relaxed); + } } void KSpinLock::Unlock() { - m_lock.unlock(); + if (m_state.exchange(0, std::memory_order_release) == 2) { + m_state.notify_one(); + } } bool KSpinLock::TryLock() { - return m_lock.try_lock(); + u32 expected = 0; + return m_state.compare_exchange_strong(expected, 1, std::memory_order_acquire, + std::memory_order_relaxed); } } // namespace Kernel |