On Sunday 25 March 2007 21:34, malc wrote: > On Sun, 25 Mar 2007, Ingo Molnar wrote: > > * Con Kolivas <[EMAIL PROTECTED]> wrote: > >> For an rsdl 0.33 patched kernel. Comments? Overhead worth it? > > > > we want to do this - and we should do this to the vanilla scheduler > > first and check the results. I've back-merged the patch to before RSDL > > and have tested it - find the patch below. Vale, could you try this > > patch against a 2.6.21-rc4-ish kernel and re-test your testcase? > > [..snip..] > > Compilation failed with: > kernel/built-in.o(.sched.text+0x564): more undefined references to > `__udivdi3' follow > > $ gcc --version | head -1 > gcc (GCC) 3.4.6 > > $ cat /proc/cpuinfo | grep cpu > cpu : 7447A, altivec supported > > Can't say i really understand why 64bit arithmetics suddenly became an > issue here.
Probably due to use of: #define NS_TO_JIFFIES(TIME) ((TIME) / (1000000000 / HZ)) #define JIFFIES_TO_NS(TIME) ((TIME) * (1000000000 / HZ)) Excuse our 64bit world while we strive to correct our 32bit blindness and fix this bug. > > Am i supposed to run the testcase and see if numbers in `/proc/stat' > now match the reality closer? To be really accurate `/proc/stat' > should be left alone methinks, because no matter how good you try the > fundamential fact that time(and consequently load percentage) is not > really devided in USER_HZ intervals will interfere with ones quest for > accurate statistics. (Wonder what this patch will do to slightly modified > hog that produced this: http://www.boblycat.org/~malc/apc/load-c2d-hog.png > but this will have to wait till i get to the PC at work) It should far more accurately represent the cpu usage without any userspace changes. -- -ck - 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/