path: root/ipc
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authorJohn Stultz <>2010-05-07 18:07:38 -0700
committerThomas Gleixner <>2010-05-10 14:24:26 +0200
commitd7e81c269db899b800e0963dc4aceece1f82a680 (patch)
treebf30c8c5ed86dbf3c71a25e0f3ab1093c19e516f /ipc
parent29f87b793da421a6ab816d991dc8dbf909dfb66a (diff)
clocksource: Add clocksource_register_hz/khz interface
How to pick good mult/shift pairs has always been difficult to describe to folks writing clocksource drivers, since it requires careful tradeoffs in adjustment accuracy vs overflow limits. Now, with the clocks_calc_mult_shift function, its much easier. However, not many clocksources have converted to using that function, and there is still the issue of the max interval length assumption being made by each clocksource driver independently. So this patch simplifies the registration process by having clocksources be registered with a hz/khz value and the registration function taking care of setting mult/shift. This should take most of the confusion out of writing a clocksource driver. Additionally it also keeps the shift size tradeoff (more accuracy vs longer possible nohz times) centralized so the timekeeping core can keep track of the assumptions being made. [ tglx: Coding style and comments fixed ] Signed-off-by: John Stultz <> LKML-Reference: <> Signed-off-by: Thomas Gleixner <>
Diffstat (limited to 'ipc')
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