Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Wolfgang Grandegger
Paul E. McKenney wrote: > On Wed, Jan 30, 2008 at 11:45:01AM +0100, Wolfgang Grandegger wrote: >> Paul E. McKenney wrote: >>> On Wed, Jan 30, 2008 at 09:18:49AM +0100, Wolfgang Grandegger wrote: Paul E. McKenney wrote: > On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote:

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Luotao Fu
Hi, On Wed, Jan 30, 2008 at 02:57:16AM -0800, Paul E. McKenney wrote: .. > > Yes, I used "$ cyclictest -n -t1 -p80 -i1000" to measure the latency. So > > far, I have not done other tests. Any recommendation? > > As no-rt load I used "while ls; do ls /bin; done" in one telnet window > > and "wh

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Paul E. McKenney
On Wed, Jan 30, 2008 at 11:45:01AM +0100, Wolfgang Grandegger wrote: > Paul E. McKenney wrote: > > On Wed, Jan 30, 2008 at 09:18:49AM +0100, Wolfgang Grandegger wrote: > >> Paul E. McKenney wrote: > >>> On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote: > Luotao Fu wrote: > >

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Wolfgang Grandegger
Paul E. McKenney wrote: > On Wed, Jan 30, 2008 at 09:18:49AM +0100, Wolfgang Grandegger wrote: >> Paul E. McKenney wrote: >>> On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote: Luotao Fu wrote: > Hi, > > Wolfgang Grandegger wrote: > .. >> Do you st

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Paul E. McKenney
On Wed, Jan 30, 2008 at 09:18:49AM +0100, Wolfgang Grandegger wrote: > Paul E. McKenney wrote: > > On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote: > >> Luotao Fu wrote: > >>> Hi, > >>> > >>> Wolfgang Grandegger wrote: > >>> .. > Do you still get high latencies with

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-30 Thread Wolfgang Grandegger
Paul E. McKenney wrote: > On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote: >> Luotao Fu wrote: >>> Hi, >>> >>> Wolfgang Grandegger wrote: >>> .. Do you still get high latencies with: CONFIG_PREEMPT_RCU_BOOST=y CONFIG_RCU_TRACE=y CONFIG_NO_H

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-29 Thread Paul E. McKenney
On Tue, Jan 29, 2008 at 02:38:04PM +0100, Wolfgang Grandegger wrote: > Luotao Fu wrote: > > Hi, > > > > Wolfgang Grandegger wrote: > > .. > >> Do you still get high latencies with: > >> > >> CONFIG_PREEMPT_RCU_BOOST=y > >> CONFIG_RCU_TRACE=y > >> CONFIG_NO_HZ is not set > >> > >> Wit

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-29 Thread Wolfgang Grandegger
Luotao Fu wrote: > Hi, > > Wolfgang Grandegger wrote: > .. >> Do you still get high latencies with: >> >> CONFIG_PREEMPT_RCU_BOOST=y >> CONFIG_RCU_TRACE=y >> CONFIG_NO_HZ is not set >> >> With this setting I have not yet realized latencies > 150us. Could you >> please give it a try?

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc - RCU issue?

2008-01-29 Thread Luotao Fu
Hi, Wolfgang Grandegger wrote: .. > Do you still get high latencies with: > > CONFIG_PREEMPT_RCU_BOOST=y > CONFIG_RCU_TRACE=y > CONFIG_NO_HZ is not set > > With this setting I have not yet realized latencies > 150us. Could you > please give it a try? If I change one of the parameter

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-28 Thread Wolfgang Grandegger
Hi Fu, Luotao Fu wrote: > Hi, > > I took some time today and went through Wolfgangs scenarios partly. Now > some results from my side. I ran my tests on a 2.6.24-rt1 > > Wolfgang Grandegger wrote: > > I also did some more measurements and made, by chance, interesting >> observations. I will sum

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-28 Thread Luotao Fu
Hi, I took some time today and went through Wolfgangs scenarios partly. Now some results from my side. I ran my tests on a 2.6.24-rt1 Wolfgang Grandegger wrote: > I also did some more measurements and made, by chance, interesting observations. I will summarize in more detail later on. Here a

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-24 Thread Wolfgang Grandegger
Wolfgang Grandegger wrote: > Hi Fu, > > Luotao Fu wrote: >> Hi folks, >> >> On Thu, Jan 17, 2008 at 11:13:26AM +0100, Wolfgang Grandegger wrote: >>> It builds and runs fine on my Icecube-MPC5200 board, now also with the >>> latency tracer enabled. That's great. Still, "cyclictest -n -p80 -i1000" >

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-23 Thread Wolfgang Grandegger
Hi Fu, Luotao Fu wrote: > Hi folks, > > On Thu, Jan 17, 2008 at 11:13:26AM +0100, Wolfgang Grandegger wrote: >> It builds and runs fine on my Icecube-MPC5200 board, now also with the >> latency tracer enabled. That's great. Still, "cyclictest -n -p80 -i1000" >> reports latencies up to 400 us and

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-23 Thread Daniel Walker
On Wed, 2008-01-23 at 15:53 +0100, Luotao Fu wrote: > I was doing some tests on my mpc5200b Board to reproduce the high latency as > measured by wolfgang. > > I ran some tests with > while [ 1 ]; do ls /bin;done > as non-rt workload, as in Wolfgangs Scenario. > Can you try enabling CRITICAL_P

Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc

2008-01-23 Thread Luotao Fu
Hi folks, On Thu, Jan 17, 2008 at 11:13:26AM +0100, Wolfgang Grandegger wrote: > It builds and runs fine on my Icecube-MPC5200 board, now also with the > latency tracer enabled. That's great. Still, "cyclictest -n -p80 -i1000" > reports latencies up to 400 us and therefore I tried to trigger and s