Messages in this thread | | | Date | Sat, 20 Sep 2008 09:59:45 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: Reading EeePC900 battery info causes stalls (was Re: How how latent should non-preemptive scheduling be?) |
| |
On Sat, 20 Sep 2008, Sitsofe Wheeler wrote: > > > I thought we had a wakeup latency tracer exacty like we have preempt and > > irq off latency tracers, Steve, where'd that go? > > I rebuilt my kernel after a make clean and wakeup was still not there. It > might be a good idea to modify the kernel documentation currently > provided with 2.6.27 if it has gone away for now (or document the extra > switches needed to turn it on if that's why it didn't show up for me)...
The wake up tracing is CONFIG_SCHED_TRACER. If you do not see "wakeup" as one of the available tracers in available_tracers, then check your dmesg and see if you have CONFIG_FTRACE_STARTUP_TEST enabled. There was a known bug that would cause the wakeup tracing to fail the test. When a trace fails the startup test, it is disabled.
-- Steve
| |