From mboxrd@z Thu Jan 1 00:00:00 1970 From: walter harms Date: Wed, 16 Aug 2006 14:12:13 +0000 Subject: Re: [KJ] timeslice calculation Message-Id: <44E327BD.5080000@bfs.de> List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kernel-janitors@vger.kernel.org there is also a high resolution timer patch with dynamic ticks that promisses a better response time. http://lwn.net/Articles/152363/ re, walter Andreas Mohr wrote: > Hi, > > On Wed, Aug 16, 2006 at 05:50:20PM +0530, Tharindu Rukshan Bamunuarachchi wrote: >> Dear All, >> >> They have changed HZ value. So, they says my timer interrupt occures >> at 1ms interval. IS it true?? >> >> Anyway, is it impossible to calculate HZ value in running linux system. >> >> Because, we wanted to have highly interactive system. So they have >> suggested change of timer interval fire. What about decrease of >> minimum time slice. > > Wanting a highly interactive system is precisely the very best reason > to go with a -ck kernel, I guess. > >>>From what I see CONFIG_HZ doesn't influence timeslice length, however. > This is because timeslice length is NOT directly related to timer tick rate. > The TIMESLICE defines in sched.c indicate the standard (*average*) > timeslice values for processes, regardless how often the timer interrupt > (which is a process rescheduling point) fires (this might be much more often > than process rescheduling actually takes place). > > If you have definite need for a lower timeslice, then I believe there's > no way around modifying those sched.c defines and recompiling. > > Note that lowering timeslice values will deteriorate your cache-hot > efficiency due to too frequently swapped processes/memory sets (IIRC the > usual time to get a cache really hot was more than 3ms on a P3 or so). > As such you might want to tend to replacing the entire scheduler instead > of doing some timeslice tweaks... > > Andreas Mohr > _______________________________________________ > Kernel-janitors mailing list > Kernel-janitors@lists.osdl.org > https://lists.osdl.org/mailman/listinfo/kernel-janitors > > > _______________________________________________ Kernel-janitors mailing list Kernel-janitors@lists.osdl.org https://lists.osdl.org/mailman/listinfo/kernel-janitors