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mirror of https://github.com/RPCS3/rpcs3.git synced 2024-11-25 04:02:42 +01:00

atomic.hpp: use native semaphores on Windows

Windows: drop keyed events
Linux: keep using native futex
Implement unused POSIX semaphore path
Implement fallback semaphore with pure std (OSX, BSD, etc)
This commit is contained in:
Nekotekina 2019-09-22 01:31:23 +03:00
parent 95c939f014
commit 9710473a2e
2 changed files with 495 additions and 113 deletions

View File

@ -15,7 +15,6 @@
#include <linux/futex.h>
#include <sys/time.h>
#include <unistd.h>
#else
#endif
#include <algorithm>
#include <ctime>
@ -25,12 +24,8 @@
#include <unordered_map>
#ifdef _WIN32
DYNAMIC_IMPORT("ntdll.dll", NtWaitForKeyedEvent, NTSTATUS(HANDLE Handle, PVOID Key, BOOLEAN Alertable, PLARGE_INTEGER Timeout));
DYNAMIC_IMPORT("ntdll.dll", NtReleaseKeyedEvent, NTSTATUS(HANDLE Handle, PVOID Key, BOOLEAN Alertable, PLARGE_INTEGER Timeout));
DYNAMIC_IMPORT("ntdll.dll", NtWaitForSingleObject, NTSTATUS(HANDLE Handle, BOOLEAN Alertable, PLARGE_INTEGER Timeout));
DYNAMIC_IMPORT("ntdll.dll", NtDelayExecution, NTSTATUS(BOOLEAN Alertable, PLARGE_INTEGER DelayInterval));
inline utils::dynamic_import<BOOL(volatile VOID* Address, PVOID CompareAddress, SIZE_T AddressSize, DWORD dwMilliseconds)> OptWaitOnAddress("kernel32.dll", "WaitOnAddress");
inline utils::dynamic_import<VOID(PVOID Address)> OptWakeByAddressSingle("kernel32.dll", "WakeByAddressSingle");
inline utils::dynamic_import<VOID(PVOID Address)> OptWakeByAddressAll("kernel32.dll", "WakeByAddressAll");
#endif
#ifndef __linux__

View File

@ -1,11 +1,24 @@
#include "atomic.hpp"
// USE_FUTEX takes precedence over USE_POSIX
#ifdef __linux__
#define USE_FUTEX
#define USE_POSIX
#endif
#include "Utilities/sync.h"
#include "Utilities/asm.h"
#ifdef USE_POSIX
#include <semaphore.h>
#endif
#include <map>
#include <mutex>
#include <condition_variable>
#include <iterator>
#include <memory>
// Total number of entries, should be a power of 2.
static constexpr std::uintptr_t s_hashtable_size = 1u << 22;
@ -22,8 +35,18 @@ static constexpr u64 s_waiter_mask = 0x7fff'0000'0000'0000;
//
static constexpr u64 s_collision_bit = 0x8000'0000'0000'0000;
#ifdef USE_FUTEX
static constexpr u64 s_sema_mask = 0;
#else
// Number of search groups (defines max semaphore count as gcount * 64)
static constexpr u32 s_sema_gcount = 64;
// Bits encoding allocated semaphore index (zero = not allocated yet)
static constexpr u64 s_sema_mask = (64 * s_sema_gcount - 1) << 2;
#endif
// Implementation detail (remaining bits out of 32 available for futex)
static constexpr u64 s_signal_mask = 0xffffffff & ~(s_waiter_mask | s_pointer_mask | s_collision_bit);
static constexpr u64 s_signal_mask = 0xffffffff & ~(s_waiter_mask | s_pointer_mask | s_collision_bit | s_sema_mask);
// Callback for wait() function, returns false if wait should return
static thread_local bool(*s_tls_wait_cb)(const void* data) = [](const void*)
@ -31,6 +54,140 @@ static thread_local bool(*s_tls_wait_cb)(const void* data) = [](const void*)
return true;
};
#ifndef USE_FUTEX
#ifdef USE_POSIX
using sema_handle = sem_t;
#elif defined(_WIN32)
using sema_handle = HANDLE;
#else
namespace
{
struct dumb_sema
{
u64 count = 0;
std::mutex mutex;
std::condition_variable cond;
};
}
using sema_handle = std::unique_ptr<dumb_sema>;
#endif
// Array of native semaphores
static sema_handle s_sema_list[64 * s_sema_gcount]{};
// Array of associated reference counters
static atomic_t<u64> s_sema_refs[64 * s_sema_gcount]{};
// Allocation bits (reserve first bit)
static atomic_t<u64> s_sema_bits[s_sema_gcount]{1};
static u32 sema_alloc()
{
// Diversify search start points to reduce contention and increase immediate success chance
#ifdef _WIN32
const u32 start = GetCurrentProcessorNumber();
#elif __linux__
const u32 start = sched_getcpu();
#else
const u32 start = __rdtsc();
#endif
for (u32 i = 0; i < s_sema_gcount * 3; i++)
{
const u32 group = (i + start) % s_sema_gcount;
const auto [bits, ok] = s_sema_bits[group].fetch_op([](u64& bits)
{
if (~bits)
{
// Set lowest clear bit
bits |= bits + 1;
return true;
}
return false;
});
if (ok)
{
// Find lowest clear bit
const u32 id = group * 64 + utils::cnttz64(~bits, false);
#ifdef USE_POSIX
// Initialize semaphore (should be very fast)
sem_init(&s_sema_list[id], 0, 0);
#elif defined(_WIN32)
if (!s_sema_list[id])
{
s_sema_list[id] = CreateSemaphoreW(nullptr, 0, 0x7fff'ffff, nullptr);
}
#else
if (!s_sema_list[id])
{
s_sema_list[id] = std::make_unique<dumb_sema>();
}
#endif
// Initialize ref counter
if (s_sema_refs[id]++)
{
std::abort();
}
return id;
}
}
return 0;
}
static void sema_free(u32 id)
{
if (id && id < 64 * s_sema_gcount)
{
// Dereference first
if (--s_sema_refs[id])
{
return;
}
#ifdef USE_POSIX
// Destroy semaphore (should be very fast)
sem_destroy(&s_sema_list[id]);
#else
// No action required
#endif
// Reset allocation bit
s_sema_bits[id / 64] &= ~(1ull << (id % 64));
}
}
static bool sema_get(u32 id)
{
if (id && id < 64 * s_sema_gcount)
{
// Increment only if the semaphore is allocated
if (s_sema_refs[id].fetch_op([](u64& refs)
{
if (refs)
{
// Increase reference from non-zero value
refs++;
}
}))
{
return true;
}
}
return false;
}
#endif
static inline bool ptr_cmp(const void* data, std::size_t size, u64 old_value, u64 mask)
{
switch (size)
@ -151,25 +308,6 @@ namespace
}
}
#if !defined(_WIN32) && !defined(__linux__)
void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_value, u64 timeout, u64 mask)
{
fallback_wait(data, size, old_value, timeout, mask);
}
void atomic_storage_futex::notify_one(const void* data)
{
fallback_notify_one(data);
}
void atomic_storage_futex::notify_all(const void* data)
{
fallback_notify_all(data);
}
#else
void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_value, u64 timeout, u64 mask)
{
if (!timeout)
@ -185,6 +323,8 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
bool fallback = false;
u32 sema_id = -1;
const auto [_, ok] = entry.fetch_op([&](u64& value)
{
if ((value & s_waiter_mask) == s_waiter_mask || (value & s_signal_mask) == s_signal_mask)
@ -193,15 +333,15 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
return false;
}
#ifndef USE_FUTEX
sema_id = (value & s_sema_mask) >> 2;
#endif
if (!value || (value & s_pointer_mask) == (iptr & s_pointer_mask))
{
// Store pointer bits
value |= (iptr & s_pointer_mask);
fallback = false;
#ifdef _WIN32
value += s_signal_mask & -s_signal_mask;
#endif
}
else
{
@ -221,13 +361,93 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
return;
}
#ifndef USE_FUTEX
for (u32 loop_count = 0; !fallback && loop_count < 7; loop_count++)
{
// Try to allocate a semaphore
if (!sema_id)
{
const u32 sema = sema_alloc();
if (!sema)
{
break;
}
sema_id = entry.atomic_op([&](u64& value) -> u32
{
if (value & s_sema_mask)
{
return (value & s_sema_mask) >> 2;
}
// Insert allocated semaphore
value += s_signal_mask & -s_signal_mask;
value |= (u64{sema} << 2);
return 0;
});
if (sema_id)
{
// Drop unnecessary allocation
sema_free(sema);
}
else
{
sema_id = sema;
break;
}
}
if (!sema_get(sema_id))
{
sema_id = 0;
continue;
}
// Try to increment sig (check semaphore validity)
const auto [_old, ok] = entry.fetch_op([&](u64& value)
{
if ((value & s_signal_mask) == s_signal_mask)
{
return false;
}
if ((value & s_sema_mask) >> 2 != sema_id)
{
return false;
}
value += s_signal_mask & -s_signal_mask;
return true;
});
if (!ok)
{
sema_free(sema_id);
sema_id = 0;
if ((_old & s_signal_mask) == s_signal_mask)
{
// Break on signal overflow
break;
}
continue;
}
break;
}
#endif
if (fallback)
{
fallback_wait(data, size, old_value, timeout, mask);
}
else if (ptr_cmp(data, size, old_value, mask) && s_tls_wait_cb(data))
else if (sema_id && ptr_cmp(data, size, old_value, mask) && s_tls_wait_cb(data))
{
#ifdef _WIN32
#ifndef USE_FUTEX
#if defined(_WIN32) && !defined(USE_POSIX)
LARGE_INTEGER qw;
qw.QuadPart = -static_cast<s64>(timeout / 100);
@ -237,12 +457,59 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
qw.QuadPart -= 1;
}
if (!NtWaitForKeyedEvent(nullptr, &entry, false, timeout + 1 ? &qw : nullptr))
if (!NtWaitForSingleObject(s_sema_list[sema_id], false, timeout + 1 ? &qw : nullptr))
{
// Return if no errors, continue if timed out
s_tls_wait_cb(nullptr);
return;
fallback = true;
}
#elif defined(USE_POSIX)
struct timespec ts;
clock_gettime(CLOCK_REALTIME, &ts);
ts.tv_sec += timeout / 1'000'000'000;
ts.tv_nsec += timeout % 1'000'000'000;
ts.tv_sec += ts.tv_nsec / 1'000'000'000;
ts.tv_nsec %= 1'000'000'000;
// It's pretty unreliable because it uses absolute time, which may jump backwards. Sigh.
if (timeout + 1)
{
if (sem_timedwait(&s_sema_list[sema_id], &ts) == 0)
{
fallback = true;
}
}
else
{
if (sem_wait(&s_sema_list[sema_id]) == 0)
{
fallback = true;
}
}
#else
dumb_sema& sema = *s_sema_list[sema_id];
std::unique_lock lock(sema.mutex);
if (timeout + 1)
{
sema.cond.wait_for(lock, std::chrono::nanoseconds(timeout), [&]
{
return sema.count > 0;
});
}
else
{
sema.cond.wait(lock, [&]
{
return sema.count > 0;
});
}
if (sema.count > 0)
{
sema.count--;
fallback = true;
}
#endif
#else
struct timespec ts;
ts.tv_sec = timeout / 1'000'000'000;
@ -252,6 +519,11 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
#endif
}
if (!sema_id)
{
fallback = true;
}
while (true)
{
// Try to decrement
@ -259,15 +531,21 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
{
if (value & s_waiter_mask)
{
#ifdef _WIN32
#ifndef USE_FUTEX
// If timeout
if (!fallback)
{
if ((value & s_signal_mask) == 0)
if ((value & s_signal_mask) == 0 || (value & s_sema_mask) >> 2 != sema_id)
{
return false;
}
value -= s_signal_mask & -s_signal_mask;
if ((value & s_signal_mask) == 0)
{
value &= ~s_sema_mask;
}
}
#endif
@ -290,22 +568,45 @@ void atomic_storage_futex::wait(const void* data, std::size_t size, u64 old_valu
break;
}
#ifdef _WIN32
#ifndef USE_FUTEX
#if defined(_WIN32) && !defined(USE_POSIX)
static LARGE_INTEGER instant{};
if (!NtWaitForKeyedEvent(nullptr, &entry, false, &instant))
if (!NtWaitForSingleObject(s_sema_list[sema_id], false, &instant))
{
break;
fallback = true;
}
#elif defined(USE_POSIX)
if (sem_trywait(&s_sema_list[sema_id]) == 0)
{
fallback = true;
}
#else
// Unreachable
std::terminate();
dumb_sema& sema = *s_sema_list[sema_id];
std::unique_lock lock(sema.mutex);
if (sema.count > 0)
{
sema.count--;
fallback = true;
}
#endif
#endif
}
#ifndef USE_FUTEX
if (sema_id)
{
sema_free(sema_id);
}
#endif
s_tls_wait_cb(nullptr);
}
#ifdef USE_FUTEX
void atomic_storage_futex::notify_one(const void* data)
{
const std::uintptr_t iptr = reinterpret_cast<std::uintptr_t>(data);
@ -316,23 +617,6 @@ void atomic_storage_futex::notify_one(const void* data)
{
if (value & s_waiter_mask && (value & s_pointer_mask) == (iptr & s_pointer_mask))
{
#ifdef _WIN32
if ((value & s_signal_mask) == 0)
{
// No relevant waiters, do nothing
return false;
}
// Try to decrement if possible
value -= s_waiter_mask & -s_waiter_mask;
value -= s_signal_mask & -s_signal_mask;
if ((value & s_waiter_mask) == 0)
{
// Reset on last waiter
value = 0;
}
#else
if ((value & s_signal_mask) == s_signal_mask)
{
// Signal overflow, do nothing
@ -347,7 +631,7 @@ void atomic_storage_futex::notify_one(const void* data)
notify_all(data);
return false;
}
#endif
return true;
}
else if (value & s_waiter_mask && value & s_collision_bit)
@ -361,11 +645,7 @@ void atomic_storage_futex::notify_one(const void* data)
if (ok)
{
#ifdef _WIN32
NtReleaseKeyedEvent(nullptr, &entry, false, nullptr);
#else
futex(reinterpret_cast<char*>(&entry) + 4 * IS_BE_MACHINE, FUTEX_WAKE_PRIVATE, 1);
#endif
}
}
@ -375,53 +655,6 @@ void atomic_storage_futex::notify_all(const void* data)
atomic_t<u64>& entry = s_hashtable[(iptr >> 2) % s_hashtable_size];
// Try to consume everything
#ifdef _WIN32
const auto [old, ok] = entry.fetch_op([&](u64& value)
{
if (value & s_waiter_mask)
{
if ((value & s_pointer_mask) == (iptr & s_pointer_mask))
{
if ((value & s_signal_mask) == 0)
{
// No relevant waiters, do nothing
return false;
}
const u64 count = (value & s_signal_mask) / (s_signal_mask & -s_signal_mask);
value -= (s_waiter_mask & -s_waiter_mask) * count;
value -= (s_signal_mask & -s_signal_mask) * count;
if ((value & s_waiter_mask) == 0)
{
// Reset on last waiter
value = 0;
}
return true;
}
if (value & s_collision_bit)
{
fallback_notify_all(data);
return false;
}
}
return false;
});
if (!ok)
{
return;
}
for (u64 count = old & s_signal_mask; count; count -= s_signal_mask & -s_signal_mask)
{
NtReleaseKeyedEvent(nullptr, &entry, false, nullptr);
}
#else
const auto [_, ok] = entry.fetch_op([&](u64& value)
{
if (value & s_waiter_mask)
@ -452,7 +685,6 @@ void atomic_storage_futex::notify_all(const void* data)
{
futex(reinterpret_cast<char*>(&entry) + 4 * IS_BE_MACHINE, FUTEX_WAKE_PRIVATE, 0x7fffffff);
}
#endif
}
#endif
@ -472,3 +704,158 @@ void atomic_storage_futex::raw_notify(const void* data)
notify_all(data);
}
}
#ifndef USE_FUTEX
void atomic_storage_futex::notify_one(const void* data)
{
const std::uintptr_t iptr = reinterpret_cast<std::uintptr_t>(data);
atomic_t<u64>& entry = s_hashtable[(iptr >> 2) % s_hashtable_size];
const u64 value = entry;
if (value & s_waiter_mask && (value & s_pointer_mask) == (iptr & s_pointer_mask))
{
if ((value & s_signal_mask) == 0 || (value & s_sema_mask) == 0)
{
// No relevant waiters, do nothing
return;
}
}
else if (value & s_waiter_mask && value & s_collision_bit)
{
fallback_notify_one(data);
return;
}
else
{
return;
}
const u32 sema_id = (value & s_sema_mask) >> 2;
if (!sema_get(sema_id))
{
return;
}
const auto [_, ok] = entry.fetch_op([&](u64& value)
{
if ((value & s_waiter_mask) == 0 || (value & s_pointer_mask) != (iptr & s_pointer_mask))
{
return false;
}
if ((value & s_signal_mask) == 0 || (value & s_sema_mask) >> 2 != sema_id)
{
return false;
}
value -= s_signal_mask & -s_signal_mask;
// Reset allocated semaphore on last waiter
if ((value & s_signal_mask) == 0)
{
value &= ~s_sema_mask;
}
return true;
});
if (ok)
{
#ifdef USE_POSIX
sem_post(&s_sema_list[sema_id]);
#elif defined(_WIN32)
ReleaseSemaphore(s_sema_list[sema_id], 1, nullptr);
#else
dumb_sema& sema = *s_sema_list[sema_id];
sema.mutex.lock();
sema.count += 1;
sema.mutex.unlock();
sema.cond.notify_one();
#endif
}
sema_free(sema_id);
}
void atomic_storage_futex::notify_all(const void* data)
{
const std::uintptr_t iptr = reinterpret_cast<std::uintptr_t>(data);
atomic_t<u64>& entry = s_hashtable[(iptr >> 2) % s_hashtable_size];
const u64 value = entry;
if (value & s_waiter_mask && (value & s_pointer_mask) == (iptr & s_pointer_mask))
{
if ((value & s_signal_mask) == 0 || (value & s_sema_mask) == 0)
{
// No relevant waiters, do nothing
return;
}
}
else if (value & s_waiter_mask && value & s_collision_bit)
{
fallback_notify_all(data);
return;
}
else
{
return;
}
const u32 sema_id = (value & s_sema_mask) >> 2;
if (!sema_get(sema_id))
{
return;
}
const auto [_, count] = entry.fetch_op([&](u64& value) -> u32
{
if ((value & s_waiter_mask) == 0 || (value & s_pointer_mask) != (iptr & s_pointer_mask))
{
return 0;
}
if ((value & s_signal_mask) == 0 || (value & s_sema_mask) >> 2 != sema_id)
{
return 0;
}
const u32 r = (value & s_signal_mask) / (s_signal_mask & -s_signal_mask);
value &= ~s_sema_mask;
value &= ~s_signal_mask;
return r;
});
#ifdef USE_POSIX
for (u32 i = 0; i < count; i++)
{
sem_post(&s_sema_list[sema_id]);
}
#elif defined(_WIN32)
if (count)
{
ReleaseSemaphore(s_sema_list[sema_id], count, nullptr);
}
#else
if (count)
{
dumb_sema& sema = *s_sema_list[sema_id];
sema.mutex.lock();
sema.count += count;
sema.mutex.unlock();
sema.cond.notify_all();
}
#endif
sema_free(sema_id);
}
#endif