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Con Kolivas wrote: > On Thursday 13 April 2006 01:25, Al Boldi wrote: > > Con Kolivas wrote: > > > mean 68.7 seconds > > > > > > range 63-73 seconds. > > > > Could this 10s skew be improved to around 1s to aid smoothness? > > It turns out to be dependant on accounting of system time which only > staircase does at the moment btw. Currently it's done on a jiffy basis. To > increase the accuracy of this would incur incredible cost which I don't > consider worth it. Is this also related to that? > > Much smoother, but I still get this choke w/ 2 eatm 9999 loops running: > > > > 9 MB 783 KB eaten in 130 msec (74 MB/s) > > 9 MB 783 KB eaten in 2416 msec (3 MB/s) <<<<<<<<<<<<< > > 9 MB 783 KB eaten in 197 msec (48 MB/s) > > > > You may have to adjust the kb to get the same effect. > > I've seen it. It's an artefact of timekeeping that it takes an > accumulation of data to get all the information. Not much I can do about > it except to have timeslices so small that they thrash the crap out of cpu > caches and completely destroy throughput. So why is this not visible in other schedulers? Are you sure this is not a priority boost problem? > The current value, 6ms at 1000HZ, is chosen because it's the largest value > that can schedule a task in less than normal human perceptible range when > two competing heavily cpu bound tasks are the same priority. At 250HZ it > works out to 7.5ms and 10ms at 100HZ. Ironically in my experimenting I > found the cpu cache improvements become much less significant above 7ms so > I'm very happy with this compromise. Would you think this is dependent on cache-size and cpu-speed? Also, what's this iso_cpu thing? > Thanks! Thank you! -- Al - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | |||||||||
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