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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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23
Kernel/Thread.cpp
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@ -567,6 +567,29 @@ void Thread::finalize_dying_threads()
}
}
void Thread::update_time_scheduled(u64 current_scheduler_time, bool is_kernel, bool no_longer_running)
{
if (m_last_time_scheduled.has_value()) {
u64 delta;
if (current_scheduler_time >= m_last_time_scheduled.value())
delta = current_scheduler_time - m_last_time_scheduled.value();
else
delta = m_last_time_scheduled.value() - current_scheduler_time; // the unlikely event that the clock wrapped
if (delta != 0) {
// Add it to the global total *before* updating the thread's value!
Scheduler::add_time_scheduled(delta, is_kernel);
auto& total_time = is_kernel ? m_total_time_scheduled_kernel : m_total_time_scheduled_user;
ScopedSpinLock scheduler_lock(g_scheduler_lock);
total_time += delta;
}
}
if (no_longer_running)
m_last_time_scheduled = {};
else
m_last_time_scheduled = current_scheduler_time;
}
bool Thread::tick()
{
if (previous_mode() == PreviousMode::KernelMode) {