Messages in this thread | | | Subject | Re: Latency data - 2.6.14-rc3-rt13 | From | Daniel Walker <> | Date | Mon, 10 Oct 2005 15:28:21 -0700 |
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On Mon, 2005-10-10 at 15:09 -0700, Mark Knecht wrote: > On 10/10/05, Daniel Walker <dwalker@mvista.com> wrote: > > On Mon, 2005-10-10 at 14:28 -0700, Mark Knecht wrote: > > > On 10/10/05, Mark Knecht <markknecht@gmail.com> wrote: > > > <SNIP> > > > > > then goto Kernel Hacking and select > > > > > "Interrupts-off critical section latency timing" > > > > > Then select "Latency tracing" > > > > > > Only had to turn on Latency Tracing. The others I had on... > > > > > > <SNIP> > > > > > > > > > > Daniel > > > > > > > > Will do. Building now. I'll be back later. > > > > > > > > > > Unfortunately I didn't think I'd be back this fast. I built the new > > > kernel and rebooted. The boot starts, gets down to the point where it > > > tells me that the preempt debug stuff is on, and then jumps to an > > > endlessly repeating error message: > > > > > > init[1]: segfault at ffffffff8010fce0 rip ffffffff8010fce0 rsp > > > 00007fffffcb09b8 error 15 > > > > > > This error repeasts endlessly until I reboot. > > > > > > Good thing I had another kernel I could boot back into! ;-) > > > > > > So, something isn't happy. Is this a -rt thing or a kernel issue? > > > > Hmm, it looks like latency tracing doesn't work on x86_64 .. I guess > > you'll have to wait till someone fixes it . > > > > Another option is to turn off "Latency Tracing" then reboot, like it was > > before but w/o the histogram. Then run, > > > > "echo 0 > /proc/sys/kernel/preempt_max_latency" > > > > Whenever a new maximum latency is observed it will log it with a stack > > trace in the system logs. You can report that back here on LKML . > > > > You can view the system log with the command "dmesg" , I think . > > > > Daniel > > > > > Yes, already that looks interesting. Do I have something going on with > acpi? This is before running Jack. I'm in Gnome.There are a lot of > these messages, but they've stopped. I suppose the 3997 is the delay? > That would coorespond with the info I sent earlier.
I think this is a false reading . Sometimes when a system goes idle it will cause interrupt disable latency that isn't real (due to process halting) . You could try turning ACPI off if you can , and turn off power management ..
Daniel
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