serenity - The Serenity Operating System 🐞

Age	Commit message (Collapse)	Author
2020-12-21	Kernel: Improve time keeping and dramatically reduce interrupt load	Tom
	This implements a number of changes related to time: * If a HPET is present, it is now used only as a system timer, unless the Local APIC timer is used (in which case the HPET timer will not trigger any interrupts at all). * If a HPET is present, the current time can now be as accurate as the chip can be, independently from the system timer. We now query the HPET main counter for the current time in CPU #0's system timer interrupt, and use that as a base line. If a high precision time is queried, that base line is used in combination with quering the HPET timer directly, which should give a much more accurate time stamp at the expense of more overhead. For faster time stamps, the more coarse value based on the last interrupt will be returned. This also means that any missed interrupts should not cause the time to drift. * The default system interrupt rate is reduced to about 250 per second. * Fix calculation of Thread CPU usage by using the amount of ticks they used rather than the number of times a context switch happened. * Implement CLOCK_REALTIME_COARSE and CLOCK_MONOTONIC_COARSE and use it for most cases where precise timestamps are not needed.
2020-12-12	Kernel: Execute timer handlers outside of irq handler	Tom
	This allows us to do things in timer handlers that involve e.g. scheduling, such as using the Lock class or unblocking threads.
2020-12-11	Kernel: Fix leaking Timer instances	Tom
	When a Timer is queued we add a reference, so whenever we remove a timer or fire it we should drop that reference. Fixes #4382
2020-12-02	Kernel: Add CLOCK_REALTIME support to the TimerQueue	Tom
	This allows us to use blocking timeouts with either monotonic or real time for all blockers. Which means that clock_nanosleep() now also supports CLOCK_REALTIME. Also, switch alarm() to use CLOCK_REALTIME as per specification.
2020-12-02	Kernel: Use TimerQueue for SIGALRM	Tom

2020-12-02	Kernel: TimerQueue::cancel_timer needs to wait if timer is executing	Tom
	We need to be able to guarantee that a timer won't be executing after TimerQueue::cancel_timer returns. In the case of multiple processors this means that we may need to wait while the timer handler finishes execution on another core. This also fixes a problem in Thread::block and Thread::wait_on where theoretically the timer could execute after the function returned and the Thread disappeared.
2020-11-30	Kernel: Move some time related code from Scheduler into TimeManagement	Tom
	Use the TimerQueue to expire blocking operations, which is one less thing the Scheduler needs to check on every iteration. Also, add a BlockTimeout class that will automatically handle relative or absolute timeouts as well as overriding timeouts (e.g. socket timeouts) more consistently. Also, rework the TimerQueue class to be able to fire events from any processor, which requires Timer to be RefCounted. Also allow creating id-less timers for use by blocking operations.
2020-08-25	Kernel: Switch singletons to use new Singleton class	Tom
	MemoryManager cannot use the Singleton class because MemoryManager::initialize is called before the global constructors are run. That caused the Singleton to be re-initialized, causing it to create another MemoryManager instance. Fixes #3226
2020-08-22	Revert "Kernel: Switch singletons to use new Singleton class"	Andreas Kling
	This reverts commit f48feae0b2a300992479abf0b2ded85e45ac6045.
2020-08-22	Revert "Kernel: Move Singleton class to AK"	Andreas Kling
	This reverts commit f0906250a181c831508a45434b9f645ff98f33e4.
2020-08-22	Revert "AK: Get rid of make_singleton function"	Andreas Kling
	This reverts commit 5a98e329d157a2db8379e0c97c6bdc1328027843.
2020-08-22	AK: Get rid of make_singleton function	Tom
	Just default the InitFunction template argument.
2020-08-22	Kernel: Move Singleton class to AK	Tom

2020-08-21	Kernel: Switch singletons to use new Singleton class	Tom
	Fixes #3226
2020-04-27	Kernel: Update TimerQueue next due timer only when necessary	Brian Gianforcaro
	Previously we blindly just called update_next_timer_due() when ever we modified the timer list. Since we know the list is sorted this is a bit wasteful, and we can do better. This change refactors the code so we only update the next due time when necessary. In places where it was possible the code was modified to directly modify the next due time, instead of having to go to the front of the list to fetch it.
2020-04-27	Kernel: Expose timers via a TimerId type	Brian Gianforcaro
	The public consumers of the timer API shouldn't need to know the how timer id's are tracked internally. Expose a typedef instead to allow the internal implementation to be protected from potential churn in the future. It's also just good API design.
2020-04-26	Kernel: Refactor TimeQueue::add_timer to use timeval	Brian Gianforcaro
	The current API of add_timer makes it hard to use as you are forced to do a bunch of time arithmetic at the caller. Ideally we would have overloads for common time types like timespec or timeval to keep the API as straight forward as possible. This change moves us in that direction. While I'm here, we should really also use the machines actual ticks per second, instead of the OPTIMAL_TICKS_PER_SECOND_RATE.
2020-02-16	Kernel: Move all code into the Kernel namespace	Andreas Kling

2020-01-18	Meta: Add license header to source files	Andreas Kling
	As suggested by Joshua, this commit adds the 2-clause BSD license as a comment block to the top of every source file. For the first pass, I've just added myself for simplicity. I encourage everyone to add themselves as copyright holders of any file they've added or modified in some significant way. If I've added myself in error somewhere, feel free to replace it with the appropriate copyright holder instead. Going forward, all new source files should include a license header.
2019-12-27	Kernel: Add kernel-level timer queue (heavily based on @juliusf's work)	Conrad Pankoff
	PR #591 defines the rationale for kernel-level timers. They're most immediately useful for TCP retransmission, but will most likely see use in many other areas as well.