Date: Thu, 20 Jan 2011 00:24:54 -0500 From: Bob Hall <rjhjr0@gmail.com> To: freebsd-questions@freebsd.org Subject: statclock vs softclock Message-ID: <20110120052454.GA2983@stainmore>
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I hope this is the correct forum. I'm reading The Design & Implementation of the FreeBSD OS by McKusick & Neville-Neil, & I'm a little confused about statclock( ) and softclock( ). According to the book, statclock( ) ticks 128 times per second, and recalculates the priority of the current process every four ticks. If the recalculated priority is less than the current priority, it reschedules the process. However, on the same page, the book says that softclock( ) recalculates priorities once per second, and also reschedules processes. I must not be understanding something, because it seems to me that the book is saying that there are two routines doing the same thing and getting in each other's way. Can someone straighten me out? http://flylib.com/books/en/2.849.1.44/1 Thanks in advance.
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