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Everywhere: Make tracking cpu usage independent from system ticks

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This switches tracking CPU usage to more accurately measure time in
user and kernel land using either the TSC or another time source.
This will also come in handy when implementing a tickless kernel mode.
This commit is contained in:
Tom 2021-07-14 21:46:32 -06:00 • committed by Andreas Kling
parent 7e77a2ec40
commit a635ff4e60
13 changed files with 174 additions and 85 deletions
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21
Kernel/Arch/x86/common/Processor.cpp
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@ -612,7 +612,10 @@ void Processor::enter_trap(TrapFrame& trap, bool raise_irq)
trap.next_trap = current_trap;
current_trap = &trap;
// The cs register of this trap tells us where we will return back to
current_thread->set_previous_mode(((trap.regs->cs & 3) != 0) ? Thread::PreviousMode::UserMode : Thread::PreviousMode::KernelMode);
auto new_previous_mode = ((trap.regs->cs & 3) != 0) ? Thread::PreviousMode::UserMode : Thread::PreviousMode::KernelMode;
if (current_thread->set_previous_mode(new_previous_mode) && trap.prev_irq_level == 0) {
current_thread->update_time_scheduled(Scheduler::current_time(), new_previous_mode == Thread::PreviousMode::KernelMode, false);
}
} else {
trap.next_trap = nullptr;
}
@ -627,25 +630,29 @@ void Processor::exit_trap(TrapFrame& trap)
smp_process_pending_messages();
if (!m_in_irq && !m_in_critical)
check_invoke_scheduler();
auto* current_thread = Processor::current_thread();
if (current_thread) {
auto& current_trap = current_thread->current_trap();
current_trap = trap.next_trap;
Thread::PreviousMode new_previous_mode;
if (current_trap) {
VERIFY(current_trap->regs);
// If we have another higher level trap then we probably returned
// from an interrupt or irq handler. The cs register of the
// new/higher level trap tells us what the mode prior to it was
current_thread->set_previous_mode(((current_trap->regs->cs & 3) != 0) ? Thread::PreviousMode::UserMode : Thread::PreviousMode::KernelMode);
new_previous_mode = ((current_trap->regs->cs & 3) != 0) ? Thread::PreviousMode::UserMode : Thread::PreviousMode::KernelMode;
} else {
// If we don't have a higher level trap then we're back in user mode.
// Unless we're a kernel process, in which case we're always in kernel mode
current_thread->set_previous_mode(current_thread->process().is_kernel_process() ? Thread::PreviousMode::KernelMode : Thread::PreviousMode::UserMode);
// Which means that the previous mode prior to being back in user mode was kernel mode
new_previous_mode = Thread::PreviousMode::KernelMode;
}
if (current_thread->set_previous_mode(new_previous_mode))
current_thread->update_time_scheduled(Scheduler::current_time(), true, false);
}
if (!m_in_irq && !m_in_critical)
check_invoke_scheduler();
}
void Processor::check_invoke_scheduler()