Messages in this thread Patch in this message | | | Date | Sat, 20 Sep 2008 17:53:20 -0400 (EDT) | From | Steven Rostedt <> | Subject | Re: Reading EeePC900 battery info causes stalls |
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On Sat, 20 Sep 2008, Sitsofe Wheeler wrote:
> Steven Rostedt wrote: > > OK, that is probably the known bug you are hitting. Simply disable the > > CONFIG_FTRACE_STARTUP_TEST and you should have the wakeup tracer. The bug is > > with the test, not the tracer, so it should not hurt you. > > Thanks - this made the wakeup tracer appear a you said. I have put two wakeup > traces up: > > http://sucs.org/~sits/test/eeepc-debug/20080920/latency_trace.txt.gz > http://sucs.org/~sits/test/eeepc-debug/20080920/trace.txt.gz > (each file is around 6Mbytes uncompressed) > > Here's a small extract of latency_trace.txt: > > > # tracer: wakeup > > # > > wakeup latency trace v1.1.5 on 2.6.27-rc6skw-dirty > > -------------------------------------------------------------------- > > latency: 3232905 us, #65620/6180619, CPU#0 | (M:desktop VP:0, KP:0, SP:0
Peter, these times are crazy, mainly due to the cpu_clock. He probably wants to use the sched_clock. Below is a patch to use it instead.
Sitsofe, I notice that the trace states "desktop". This means that you are running with CONFIG_PREEMPT_VOLUNTARY. You want CONFIG_PREEMPT.
[...] > > Is it intentional that the last event has a time earlier closer to that of the > first event? >
Change the config, and see what you get with this patch:
Note this is not compiled tested:
--- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Index: linus.git/kernel/trace/trace.c =================================================================== --- linus.git.orig/kernel/trace/trace.c 2008-09-20 17:49:00.000000000 -0400 +++ linus.git/kernel/trace/trace.c 2008-09-20 17:49:35.000000000 -0400 @@ -60,7 +60,7 @@ ns2usecs(cycle_t nsec) cycle_t ftrace_now(int cpu) { - return cpu_clock(cpu); + return sched_clock(); } /*
-- Steve
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