Messages in this thread | | | Subject | Re: [PATCH] 2.6.17-rt add clockevent to ixp4xx | From | Thomas Gleixner <> | Date | Thu, 13 Jul 2006 21:07:54 +0200 |
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On Thu, 2006-07-13 at 07:41 -0700, Daniel Walker wrote: > On Thu, 2006-07-13 at 10:53 +0000, Milan Svoboda wrote: > > Hello, > > > > there are patches that enable clock event on ixp4xx platform. This should > > enable high resolution timers... Option for hrtimers in menuconfig is > > also enabled. > > > > I tested it on nanosleep test program (included in attachments) and obtained > > this results: > > > > requested: 899000 us, got: 899159 us, diff: -159 us > > requested: 897000 us, got: 897209 us, diff: -209 us > > requested: 895000 us, got: 899803 us, diff: -4803 us > > requested: 893000 us, got: 899425 us, diff: -6425 us > > requested: 891000 us, got: 899806 us, diff: -8806 us > > requested: 889000 us, got: 890142 us, diff: -1142 us > > requested: 887000 us, got: 889873 us, diff: -2873 us > > requested: 885000 us, got: 888096 us, diff: -3096 us > > I'd turn off some of the debugging options, and retest. For instance, > the pi-list debugging option will cause arbitrary latency, which you > seem to show in your results. Normally with PREEMPT_RT turned on you > would expect the timers to trigger within a constant amount of time from > when they are suppose to.
No, the time differences looks like the high res mode never gets switched on. its oszillating between 0 and 10ms, which is the usual behaviour for a non hrt kernel.
Also I would recommend to test without preempt-rt in the first place. Preempt-rt on ARM is not really well tested, so you dont fight two battles at once.
tglx
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