Date: Mon, 7 Jul 2003 14:42:10 -0400 (EDT) From: Daniel Eischen <eischen@vigrid.com> To: Petri Helenius <pete@he.iki.fi> Cc: freebsd-threads@freebsd.org Subject: Re: thread scheduling priority Message-ID: <Pine.GSO.4.10.10307071436550.4037-100000@pcnet5.pcnet.com> In-Reply-To: <3F0994CB.6070403@he.iki.fi>
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On Mon, 7 Jul 2003, Petri Helenius wrote: > Daniel Eischen wrote: > > >Mutexes are implemented using direct handoff (I think that's the > >term). Once a mutex is released, it is given to the next thread > >that is waiting on it and that thread is then marked runnable. > >Idle KSEs are suppose to be woken whenever there are runnable > >threads. > > > > > So when the main thread unlocks the mutex there are two runnable threads, > which one keeps running? The current thread. As I said before, if there are idle KSEs, then one is woken to run the newly runnable thread. > > >For now, just see if things work better with 1 CPU defined. > >If not, then all this talk about multiple KSEs isn't your > >problem; it is something else. > > > > > It definetly runs a lot better, however not as good as I would expect if > the running thread would be switched to the higher scheduling priority > thread immediately on the mutex release. Should that happen or does > it wait until the other thread hits a blocking condition ? It waits until either you hit a blocking condition or the quantum expires. The library is not (yet) smart enough to switch out the current thread after the unlock if the new owner has a higher priority. We could do that, but if there are other KSEs that can run the new thread, then they should get it. -- Dan Eischen
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