From 555866f8dcb98897688d5d7b0e6c6cca55ac069f Mon Sep 17 00:00:00 2001
From: Fernando Sahmkow <fsahmkow27@gmail.com>
Date: Mon, 9 Sep 2019 21:37:29 -0400
Subject: [PATCH] Core Timing: Rework Core Timing to run all cores evenly.
---
src/core/arm/dynarmic/arm_dynarmic.cpp | 2 +-
src/core/arm/unicorn/arm_unicorn.cpp | 2 +-
src/core/core_cpu.cpp | 14 ++----
src/core/core_timing.cpp | 66 +++++++++++++++++++-------
src/core/core_timing.h | 24 ++++++++--
src/core/cpu_core_manager.cpp | 19 +++++---
6 files changed, 89 insertions(+), 38 deletions(-)
diff --git a/src/core/arm/dynarmic/arm_dynarmic.cpp b/src/core/arm/dynarmic/arm_dynarmic.cpp
index f1506b3728..4d2e99ed00 100644
--- a/src/core/arm/dynarmic/arm_dynarmic.cpp
+++ b/src/core/arm/dynarmic/arm_dynarmic.cpp
@@ -116,7 +116,7 @@ public:
num_interpreted_instructions = 0;
}
u64 GetTicksRemaining() override {
- return std::max(parent.system.CoreTiming().GetDowncount(), 0);
+ return std::max<s64>(parent.system.CoreTiming().GetDowncount(), 0LL);
}
u64 GetCNTPCT() override {
return Timing::CpuCyclesToClockCycles(parent.system.CoreTiming().GetTicks());
diff --git a/src/core/arm/unicorn/arm_unicorn.cpp b/src/core/arm/unicorn/arm_unicorn.cpp
index 97d5c2a8ad..3f91b06d4a 100644
--- a/src/core/arm/unicorn/arm_unicorn.cpp
+++ b/src/core/arm/unicorn/arm_unicorn.cpp
@@ -156,7 +156,7 @@ void ARM_Unicorn::Run() {
if (GDBStub::IsServerEnabled()) {
ExecuteInstructions(std::max(4000000, 0));
} else {
- ExecuteInstructions(std::max(system.CoreTiming().GetDowncount(), 0));
+ ExecuteInstructions(std::max<s64>(system.CoreTiming().GetDowncount(), 0LL));
}
}
diff --git a/src/core/core_cpu.cpp b/src/core/core_cpu.cpp
index 21c410e342..6bd9639c6e 100644
--- a/src/core/core_cpu.cpp
+++ b/src/core/core_cpu.cpp
@@ -85,24 +85,16 @@ void Cpu::RunLoop(bool tight_loop) {
// instead advance to the next event and try to yield to the next thread
if (Kernel::GetCurrentThread() == nullptr) {
LOG_TRACE(Core, "Core-{} idling", core_index);
-
- if (IsMainCore()) {
- // TODO(Subv): Only let CoreTiming idle if all 4 cores are idling.
- core_timing.Idle();
- core_timing.Advance();
- }
-
+ core_timing.Idle();
+ core_timing.Advance();
PrepareReschedule();
} else {
- if (IsMainCore()) {
- core_timing.Advance();
- }
-
if (tight_loop) {
arm_interface->Run();
} else {
arm_interface->Step();
}
+ core_timing.Advance();
}
Reschedule();
diff --git a/src/core/core_timing.cpp b/src/core/core_timing.cpp
index a58f7b131d..6da2dcfb46 100644
--- a/src/core/core_timing.cpp
+++ b/src/core/core_timing.cpp
@@ -15,7 +15,7 @@
namespace Core::Timing {
-constexpr int MAX_SLICE_LENGTH = 20000;
+constexpr int MAX_SLICE_LENGTH = 10000;
struct CoreTiming::Event {
s64 time;
@@ -38,10 +38,14 @@ CoreTiming::CoreTiming() = default;
CoreTiming::~CoreTiming() = default;
void CoreTiming::Initialize() {
- downcount = MAX_SLICE_LENGTH;
+ for (std::size_t core = 0; core < num_cpu_cores; core++) {
+ downcounts[core] = MAX_SLICE_LENGTH;
+ time_slice[core] = MAX_SLICE_LENGTH;
+ }
slice_length = MAX_SLICE_LENGTH;
global_timer = 0;
idled_cycles = 0;
+ current_context = 0;
// The time between CoreTiming being initialized and the first call to Advance() is considered
// the slice boundary between slice -1 and slice 0. Dispatcher loops must call Advance() before
@@ -110,7 +114,7 @@ void CoreTiming::UnscheduleEvent(const EventType* event_type, u64 userdata) {
u64 CoreTiming::GetTicks() const {
u64 ticks = static_cast<u64>(global_timer);
if (!is_global_timer_sane) {
- ticks += slice_length - downcount;
+ ticks += time_slice[current_context] - downcounts[current_context];
}
return ticks;
}
@@ -120,7 +124,7 @@ u64 CoreTiming::GetIdleTicks() const {
}
void CoreTiming::AddTicks(u64 ticks) {
- downcount -= static_cast<int>(ticks);
+ downcounts[current_context] -= static_cast<s64>(ticks);
}
void CoreTiming::ClearPendingEvents() {
@@ -141,22 +145,36 @@ void CoreTiming::RemoveEvent(const EventType* event_type) {
void CoreTiming::ForceExceptionCheck(s64 cycles) {
cycles = std::max<s64>(0, cycles);
- if (downcount <= cycles) {
+ if (downcounts[current_context] <= cycles) {
return;
}
// downcount is always (much) smaller than MAX_INT so we can safely cast cycles to an int
// here. Account for cycles already executed by adjusting the g.slice_length
- slice_length -= downcount - static_cast<int>(cycles);
- downcount = static_cast<int>(cycles);
+ slice_length -= downcounts[current_context] - static_cast<int>(cycles);
+ downcounts[current_context] = static_cast<int>(cycles);
+}
+
+std::optional<u64> CoreTiming::NextAvailableCore(const s64 needed_ticks) const {
+ const u64 original_context = current_context;
+ u64 next_context = (original_context + 1) % num_cpu_cores;
+ while (next_context != original_context) {
+ if (time_slice[next_context] >= needed_ticks) {
+ return {next_context};
+ } else if (time_slice[next_context] >= 0) {
+ return {};
+ }
+ next_context = (next_context + 1) % num_cpu_cores;
+ }
+ return {};
}
void CoreTiming::Advance() {
std::unique_lock<std::mutex> guard(inner_mutex);
- const int cycles_executed = slice_length - downcount;
+ const int cycles_executed = time_slice[current_context] - downcounts[current_context];
+ time_slice[current_context] = std::max<s64>(0, downcounts[current_context]);
global_timer += cycles_executed;
- slice_length = MAX_SLICE_LENGTH;
is_global_timer_sane = true;
@@ -173,24 +191,40 @@ void CoreTiming::Advance() {
// Still events left (scheduled in the future)
if (!event_queue.empty()) {
- slice_length = static_cast<int>(
- std::min<s64>(event_queue.front().time - global_timer, MAX_SLICE_LENGTH));
+ s64 needed_ticks = std::min<s64>(event_queue.front().time - global_timer, MAX_SLICE_LENGTH);
+ const auto next_core = NextAvailableCore(needed_ticks);
+ if (next_core) {
+ downcounts[*next_core] = needed_ticks;
+ }
}
- downcount = slice_length;
+ downcounts[current_context] = time_slice[current_context];
+}
+
+void CoreTiming::ResetRun() {
+ for (std::size_t core = 0; core < num_cpu_cores; core++) {
+ downcounts[core] = MAX_SLICE_LENGTH;
+ time_slice[core] = MAX_SLICE_LENGTH;
+ }
+ current_context = 0;
+ // Still events left (scheduled in the future)
+ if (!event_queue.empty()) {
+ s64 needed_ticks = std::min<s64>(event_queue.front().time - global_timer, MAX_SLICE_LENGTH);
+ downcounts[current_context] = needed_ticks;
+ }
}
void CoreTiming::Idle() {
- idled_cycles += downcount;
- downcount = 0;
+ idled_cycles += downcounts[current_context];
+ downcounts[current_context] = 0;
}
std::chrono::microseconds CoreTiming::GetGlobalTimeUs() const {
return std::chrono::microseconds{GetTicks() * 1000000 / BASE_CLOCK_RATE};
}
-int CoreTiming::GetDowncount() const {
- return downcount;
+s64 CoreTiming::GetDowncount() const {
+ return downcounts[current_context];
}
} // namespace Core::Timing
diff --git a/src/core/core_timing.h b/src/core/core_timing.h
index 161c7007da..ec0a6d2c09 100644
--- a/src/core/core_timing.h
+++ b/src/core/core_timing.h
@@ -7,6 +7,7 @@
#include <chrono>
#include <functional>
#include <mutex>
+#include <optional>
#include <string>
#include <unordered_map>
#include <vector>
@@ -104,7 +105,19 @@ public:
std::chrono::microseconds GetGlobalTimeUs() const;
- int GetDowncount() const;
+ void ResetRun();
+
+ s64 GetDowncount() const;
+
+ void SwitchContext(u64 new_context) {
+ current_context = new_context;
+ }
+
+ bool CurrentContextCanRun() const {
+ return time_slice[current_context] > 0;
+ }
+
+ std::optional<u64> NextAvailableCore(const s64 needed_ticks) const;
private:
struct Event;
@@ -112,10 +125,15 @@ private:
/// Clear all pending events. This should ONLY be done on exit.
void ClearPendingEvents();
+ static constexpr u64 num_cpu_cores = 4;
+
s64 global_timer = 0;
s64 idled_cycles = 0;
- int slice_length = 0;
- int downcount = 0;
+ s64 slice_length = 0;
+ std::array<s64, num_cpu_cores> downcounts{};
+ // Slice of time assigned to each core per run.
+ std::array<s64, num_cpu_cores> time_slice{};
+ u64 current_context = 0;
// Are we in a function that has been called from Advance()
// If events are scheduled from a function that gets called from Advance(),
diff --git a/src/core/cpu_core_manager.cpp b/src/core/cpu_core_manager.cpp
index 8fcb4eeb15..e022e6a608 100644
--- a/src/core/cpu_core_manager.cpp
+++ b/src/core/cpu_core_manager.cpp
@@ -6,6 +6,7 @@
#include "core/arm/exclusive_monitor.h"
#include "core/core.h"
#include "core/core_cpu.h"
+#include "core/core_timing.h"
#include "core/cpu_core_manager.h"
#include "core/gdbstub/gdbstub.h"
#include "core/settings.h"
@@ -122,13 +123,19 @@ void CpuCoreManager::RunLoop(bool tight_loop) {
}
}
- for (active_core = 0; active_core < NUM_CPU_CORES; ++active_core) {
- cores[active_core]->RunLoop(tight_loop);
- if (Settings::values.use_multi_core) {
- // Cores 1-3 are run on other threads in this mode
- break;
+ auto& core_timing = system.CoreTiming();
+ core_timing.ResetRun();
+ bool keep_running{};
+ do {
+ keep_running = false;
+ for (active_core = 0; active_core < NUM_CPU_CORES; ++active_core) {
+ core_timing.SwitchContext(active_core);
+ if (core_timing.CurrentContextCanRun()) {
+ cores[active_core]->RunLoop(tight_loop);
+ }
+ keep_running |= core_timing.CurrentContextCanRun();
}
- }
+ } while (keep_running);
if (GDBStub::IsServerEnabled()) {
GDBStub::SetCpuStepFlag(false);