Date: Sat, 1 Aug 2015 14:24:16 +0800 From: Erich Dollansky <erichsfreebsdlist@alogt.com> To: freebsd-threads@freebsd.org Subject: pthread_setprio seems to have no effect on a Raspberry Message-ID: <20150801142416.24f39ba1@X220.alogt.com>
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Hi, I wondered that a multi threaded program of mine behaved strangely on a Raspberry B+. So, it is the old single core version. Not matter what priorities I give to two threads, I get the same result. While one thread generates messages and activates a condition, the second thread reads the condition with pthread_cond_wait. I assume that on a single core system the reading thread should only become active after the condition is set ejrm the feeding thread has a lower priority than the reading thread. Reality is that the feeding thread is writing first all messages and the reading threads starts reading them only after the feeding thread stops feeding no matter which thread has the higher priority. I used priority values like + and - 100, + and - 1, 0 and +1, 0 and -1 and 1 and 2 in all possible combinations. When I run the same source on a multi core x86, it looks like one core is generating while another core is reading. This is what I would expect under these condition. All other settings for the two threads are default. Does anyone have an idea? Erich
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