summaryrefslogtreecommitdiff
path: root/Kernel/Time/APICTimer.h
AgeCommit message (Collapse)Author
2021-04-29Everywhere: Use "the SerenityOS developers." in copyright headersLinus Groh
We had some inconsistencies before: - Sometimes "The", sometimes "the" - Sometimes trailing ".", sometimes no trailing "." I picked the most common one (lowecase "the", trailing ".") and applied it to all copyright headers. By using the exact same string everywhere we can ensure nothing gets missed during a global search (and replace), and that these inconsistencies are not spread any further (as copyright headers are commonly copied to new files).
2021-04-22Everything: Move to SPDX license identifiers in all files.Brian Gianforcaro
SPDX License Identifiers are a more compact / standardized way of representing file license information. See: https://spdx.dev/resources/use/#identifiers This was done with the `ambr` search and replace tool. ambr --no-parent-ignore --key-from-file --rep-from-file key.txt rep.txt *
2021-02-28Kernel: Fix GenericInterruptHandler problems with virtual functionsTom
Because registering and unregistering interrupt handlers triggers calls to virtual functions, we can't do this in the constructor and destructor. Fixes #5539
2020-12-21Kernel: Improve time keeping and dramatically reduce interrupt loadTom
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.
2020-10-25Kernel: Set up and calibrate APIC timer, and enable timer on all CPUsTom
This enables the APIC timer on all CPUs, which means Scheduler::timer_tick is now called on all CPUs independently. We still don't do anything on the APs as it instantly crashes due to a number of other problems.