On Sun, 20 Mar 2005, Jan Engelhardt wrote: > Hello, > > > I have found that FreeBSD has a very good precision of small sleeps -- > what's holding Linux back from doing the same? Using the code snippet below, > FBSD yields between 2 and 80 us on the average while Linux is at > "constantly" ~100 (with HZ=1000) and ~1000 (HZ=100). > Running your program here I see even worse values than that on 2.6.11-mm4 and it's also interresting to see that for a lot of continuous runs the values reported drop steadily and eventually settle around ~1100, but if I insert a sleep 1 between runs, then I see a steady ~1000 reported. This is all with HZ = 1000
[EMAIL PROTECTED]:~/download/kernel/linux-2.6.11-mm4$ for i in `seq 1 40`; do ./a.out ; done 1414 us 1434 us 1423 us 1424 us 1433 us 1423 us 1420 us 1439 us 1434 us 1433 us 1463 us 1462 us 1450 us 1431 us 1403 us 1391 us 1376 us 1364 us 1362 us 1344 us 1353 us 1353 us 1334 us 1323 us 1313 us 1314 us 1293 us 1293 us 1273 us 1274 us 1271 us 1264 us 1264 us 1244 us 1244 us 1214 us 1214 us 1214 us 1183 us 1183 us [EMAIL PROTECTED]:~/download/kernel/linux-2.6.11-mm4$ for i in `seq 1 10`; do (./a.out ; sleep 1) ; done 1113 us 997 us 997 us 998 us 997 us 997 us 996 us 997 us 996 us 996 us - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
