Searched hist:cd9d9e5417583b89e1d0a505182ebc33e4d1fad3 (Results 1 – 2 of 2) sorted by relevance
| /freebsd/sys/sys/ |
| H A D | clock.h | diff cd9d9e5417583b89e1d0a505182ebc33e4d1fad3 Mon Jul 31 03:18:21 CEST 2017 Ian Lepore <ian@FreeBSD.org> Add clock_schedule(), a feature that allows realtime clock drivers to
request that their clock_settime() methods be called at a given offset
from top-of-second. This adds a timeout_task to the rtc_instance so that
each clock can be separately added to taskqueue_thread with the scheduling
it prefers, instead of looping through all the clocks at once with a
single task on taskqueue_thread. If a driver doesn't call clock_schedule()
the default is the old behavior: clock_settime() is queued immediately.
The motivation behind this is that I was on the path of adding identical
code to a third RTC driver to figure out a delta to top-of-second and
sleep for that amount of time because writing the the RTC registers resets
the hardware's concept of top-of-second. (Sometimes it's not top-of-second,
some RTC clocks tick over a half second after you set their time registers.)
Worst-case would be to sleep for almost a full second, which is a rude thing
to do on a shared task queue thread.
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| /freebsd/sys/kern/ |
| H A D | subr_rtc.c | diff cd9d9e5417583b89e1d0a505182ebc33e4d1fad3 Mon Jul 31 03:18:21 CEST 2017 Ian Lepore <ian@FreeBSD.org> Add clock_schedule(), a feature that allows realtime clock drivers to
request that their clock_settime() methods be called at a given offset
from top-of-second. This adds a timeout_task to the rtc_instance so that
each clock can be separately added to taskqueue_thread with the scheduling
it prefers, instead of looping through all the clocks at once with a
single task on taskqueue_thread. If a driver doesn't call clock_schedule()
the default is the old behavior: clock_settime() is queued immediately.
The motivation behind this is that I was on the path of adding identical
code to a third RTC driver to figure out a delta to top-of-second and
sleep for that amount of time because writing the the RTC registers resets
the hardware's concept of top-of-second. (Sometimes it's not top-of-second,
some RTC clocks tick over a half second after you set their time registers.)
Worst-case would be to sleep for almost a full second, which is a rude thing
to do on a shared task queue thread.
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