Messages in this thread | | | Date | Mon, 22 Sep 2008 07:24:51 +0100 | From | Sitsofe Wheeler <> | Subject | Re: Reading EeePC900 battery info causes stalls |
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Steven Rostedt wrote: > 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:
OK I've made the changes you suggested. Without preempt enabled the last event will have a stamp closer to the first event and the times are very high. With preempt enabled that beahviour has gone. Here are results with preempt enabled:
latency: 19657 us, #3268/3268, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0): http://sucs.org/~sits/test/eeepc-debug/20080922/preempt/ath5k/latency_trace.txt
latency: 104 us, #182/182, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0) http://sucs.org/~sits/test/eeepc-debug/20080922/preempt/unplug/latency_trace.txt
latency: 95 us, #134/134, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0): http://sucs.org/~sits/test/eeepc-debug/20080922/preempt/acpi/latency_trace.txt
latency: 91 us, #152/152, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0) http://sucs.org/~sits/test/eeepc-debug/20080922/preempt/touchpad/latency_trace.txt
Are these the type of latencies to be expected with preemption on?
-- Sitsofe | http://sucs.org/~sits/
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