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serenity/Kernel/Scheduler.h
Tom 7e77a2ec40 Everywhere: Improve CPU usage calculation
As threads come and go, we can't simply account for how many time
slices the threads at any given point may have been using. We need to
also account for threads that have since disappeared. This means we
also need to track how many time slices we have expired globally.

However, because this doesn't account for context switches outside of
the system timer tick values may still be under-reported. To solve this
we will need to track more accurate time information on each context
switch.

This also fixes top's cpu usage calculation which was still based on
the number of context switches.

Fixes #6473
2021-07-18 22:08:26 +02:00

60 lines
1.7 KiB
C++

/*
* Copyright (c) 2018-2020, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/Assertions.h>
#include <AK/Function.h>
#include <AK/IntrusiveList.h>
#include <AK/Types.h>
#include <Kernel/Forward.h>
#include <Kernel/SpinLock.h>
#include <Kernel/Time/TimeManagement.h>
#include <Kernel/UnixTypes.h>
namespace Kernel {
struct RegisterState;
extern Thread* g_finalizer;
extern WaitQueue* g_finalizer_wait_queue;
extern Atomic<bool> g_finalizer_has_work;
extern RecursiveSpinLock g_scheduler_lock;
struct TotalTicksScheduled {
u64 total { 0 };
u64 total_kernel { 0 };
};
class Scheduler {
public:
static void initialize();
static Thread* create_ap_idle_thread(u32 cpu);
static void set_idle_thread(Thread* idle_thread);
static void timer_tick(const RegisterState&);
[[noreturn]] static void start();
static bool pick_next();
static bool yield();
static void yield_from_critical();
static bool context_switch(Thread*);
static void enter_current(Thread& prev_thread, bool is_first);
static void leave_on_first_switch(u32 flags);
static void prepare_after_exec();
static void prepare_for_idle_loop();
static Process* colonel();
static void idle_loop(void*);
static void invoke_async();
static void notify_finalizer();
static Thread& pull_next_runnable_thread();
static Thread* peek_next_runnable_thread();
static bool dequeue_runnable_thread(Thread&, bool = false);
static void queue_runnable_thread(Thread&);
static void dump_scheduler_state(bool = false);
static bool is_initialized();
static TotalTicksScheduled get_total_ticks_scheduled();
};
}