clock_getres() and real resolution

Dmitry Antipov dmitry.antipov at linaro.org
Wed Feb 8 16:31:03 UTC 2012


IIUC, an idea behind clock_getres() is to give a hint about the resolution of
specified clock. This hint may be used by an application programmer to check whether
this clock is suitable for a some purpose. So why clock_getres() always returns
something like {0, 1} (if hrtimers are enabled) regardless of the underlying platform's
real numbers?

For example, OMAP4's real resolution of CLOCK_REALTIME is 30.5us for 32K timer and 26ns
for MPU timer. Such a difference definitely makes sense - but clock_getres(CLOCK_REALTIME,..)
always returns {0, KTIME_HIGH_RES}. Since this behavior causes a confusion like
http://lists.linaro.org/pipermail/linaro-dev/2012-February/010112.html, I'm considering
this as a stupid misfeature.

Dmitry



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