Re: nanosecond debiting cv_timedwait

[Taylor R Campbell <campbell+netbsd-tech-kern%mumble.net@localhost>]

   Date: Fri, 20 Mar 2015 18:37:50 +0100
   From: Joerg Sonnenberger <joerg%britannica.bec.de@localhost>

   On Fri, Mar 20, 2015 at 01:37:59PM +0000, Taylor R Campbell wrote:
   > Objections?

   Only thing to consider is whether we want to hardwire timespec here or
   not switch to bintime. It makes for nicer computations in the rest of
   the code later.

True, although since this happens only when the LWP is about to sleep,
I'm inclined to suspect the cost of nanotime computations over bintime
computations is negligible.  We could also add another cv_timedwaitbt
or something.

I'm also tempted to just pass a pointer to uint64_t number of
nanoseconds instead of struct timespec, since waits beyond that number
of nanoseconds are pretty much guaranteed to be wrong.