There is already a suite HRT of tests they include a nanosleep jitter test with 8 or 9 other tests..
find them inside the hrt-support patch at http://high-res-timer.sf.net Daniel On Wed, 2005-08-31 at 11:01 -0400, Steven Rostedt wrote: > Thomas, > > I just was wondering how the HR Timers were in the latest -rtX patch and > wrote my own little jitter test using nanosleep. Here's the results: > > On vanilla 2.6.13-rc7-git1 (Yes I need to get over to 2.6.13) > > # ./jitter > starting calibrate > finished calibrate: 2133.9060MHz 2133906034 > time slept: 0.010000000 sec: 0 nsec: 10000000 > max: 0.011997701 > min: 0.011890522 > avg: 0.011993485 > greatest time over: 1997.701 usecs > never ran under (good!) > average time over: 1993.485 usecs > > On 2.6.13-rt3: > > # ./jitter > starting calibrate > finished calibrate: 2133.2960MHz 2133295991 > time slept: 0.010000000 sec: 0 nsec: 10000000 > max: 0.010034857 > min: 0.010006309 > avg: 0.010009213 > greatest time over: 34.857 usecs > never ran under (good!) > average time over: 9.213 usecs > > > Not bad. I then ran a clean kernel compile as root with a -j3 (this is > an 2x SMP machine), and tried the test again. > > # ./jitter > starting calibrate > finished calibrate: 2133.3005MHz 2133300491 > time slept: 0.010000000 sec: 0 nsec: 10000000 > max: 0.010044836 > min: 0.010014244 > avg: 0.010030741 > greatest time over: 44.836 usecs > never ran under (good!) > average time over: 30.741 usecs > > > Since the ticks per second is also calculated here, I ran it again using > the calibration of the first run (still running that make): > > ./jitter -c 2133295991 > passed in calibrate: 2133.2960MHz 2133295991 > time slept: 0.010000000 sec: 0 nsec: 10000000 > max: 0.010051293 > min: 0.010012155 > avg: 0.010030237 > greatest time over: 51.293 usecs > never ran under (good!) > average time over: 30.237 usecs > > And once more using the calibration found by 2.6.13-rc7-git1 (still > running that make): > > # ./jitter -c 2133906034 > passed in calibrate: 2133.9060MHz 2133906034 > time slept: 0.010000000 sec: 0 nsec: 10000000 > max: 0.010058339 > min: 0.010016418 > avg: 0.010025571 > greatest time over: 58.339 usecs > never ran under (good!) > average time over: 25.571 usecs > > > Some info on my machine: > > $ cat /proc/cpuinfo > processor : 0 > vendor_id : AuthenticAMD > cpu family : 6 > model : 10 > model name : AMD Athlon(tm) MP 2800+ > stepping : 0 > cpu MHz : 2133.286 > cache size : 512 KB > fdiv_bug : no > hlt_bug : no > f00f_bug : no > coma_bug : no > fpu : yes > fpu_exception : yes > cpuid level : 1 > wp : yes > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge > mca cmov pat pse36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow > bogomips : 4259.84 > > processor : 1 > vendor_id : AuthenticAMD > cpu family : 6 > model : 10 > model name : AMD Athlon(tm) Processor > stepping : 0 > cpu MHz : 2133.286 > cache size : 512 KB > fdiv_bug : no > hlt_bug : no > f00f_bug : no > coma_bug : no > fpu : yes > fpu_exception : yes > cpuid level : 1 > wp : yes > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge > mca cmov pat pse36 mmx fxsr sse syscall mp mmxext 3dnowext 3dnow > bogomips : 4259.84 > > And attached is the jitter.c test. Must be run as root since it ups the > priority to the max. > > Have fun, > > -- Steve > - 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/
