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Kernel: Let TimeManagement keep epoch time as timespec

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Previously, it was kept as just a time_t and the sub-second
offset was inferred from the monotonic clock. This means that
sub-second time adjustments were ignored.

Now that `ntpquery -s` can pass in a time with sub-second
precision, it makes sense to keep time at that granularity
in the kernel.

After this, `ntpquery -s` immediately followed by `ntpquery` shows
an offset of 0.02s (that is, on the order of network roundtrip time)
instead of up to 0.75s previously.
This commit is contained in:
Nico Weber 2020-09-06 19:52:24 -04:00 • committed by Andreas Kling
parent 4ac5cc2461
commit e8131f503d
3 changed files with 22 additions and 15 deletions
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26
Kernel/Time/TimeManagement.cpp
View file

@ -25,6 +25,7 @@
*/
#include <AK/Singleton.h>
#include <AK/Time.h>
#include <Kernel/ACPI/Parser.h>
#include <Kernel/CommandLine.h>
#include <Kernel/Scheduler.h>
@ -52,15 +53,20 @@ bool TimeManagement::is_system_timer(const HardwareTimer& timer) const
return &timer == m_system_timer.ptr();
}
void TimeManagement::set_epoch_time(time_t value)
void TimeManagement::set_epoch_time(timespec ts)
{
timespec ticks = { 0, (long)ticks_this_second() * (long)1'000'000 };
timespec_sub(ts, ticks, ts);
InterruptDisabler disabler;
m_epoch_time = value;
m_epoch_time = ts;
}
time_t TimeManagement::epoch_time() const
timespec TimeManagement::epoch_time() const
{
return m_epoch_time;
timespec ts = m_epoch_time;
timespec ticks = { 0, (long)ticks_this_second() * (long)1'000'000 };
timespec_add(ts, ticks, ts);
return ts;
}
void TimeManagement::initialize()
@ -94,14 +100,14 @@ TimeManagement::TimeManagement()
if (ACPI::is_enabled()) {
if (!ACPI::Parser::the()->x86_specific_flags().cmos_rtc_not_present) {
RTC::initialize();
m_epoch_time += boot_time();
m_epoch_time.tv_sec += boot_time();
} else {
klog() << "ACPI: RTC CMOS Not present";
}
} else {
// We just assume that we can access RTC CMOS, if ACPI isn't usable.
RTC::initialize();
m_epoch_time += boot_time();
m_epoch_time.tv_sec += boot_time();
}
if (probe_non_legacy_hardware_timers) {
if (!probe_and_set_non_legacy_hardware_timers())
@ -116,8 +122,10 @@ TimeManagement::TimeManagement()
timeval TimeManagement::now_as_timeval()
{
auto* time_management = s_the.ptr();
return { time_management->epoch_time(), (suseconds_t)time_management->ticks_this_second() * (suseconds_t)1000 };
timespec ts = s_the.ptr()->epoch_time();
timeval tv;
timespec_to_timeval(ts, tv);
return tv;
}
Vector<HardwareTimer*> TimeManagement::scan_and_initialize_periodic_timers()
@ -230,7 +238,7 @@ void TimeManagement::increment_time_since_boot(const RegisterState&)
if (++m_ticks_this_second >= m_time_keeper_timer->ticks_per_second()) {
// FIXME: Synchronize with other clock somehow to prevent drifting apart.
++m_seconds_since_boot;
++m_epoch_time;
++m_epoch_time.tv_sec;
m_ticks_this_second = 0;
}
}