hi peter: 2014-01-17 13:41 GMT+08:00 Peter Teoh <htmldeveloper@gmail.com>:
http://stackoverflow.com/questions/15383259/are-there-any-kernel-tools-avail...
checkout cyclictest. I have checked cyclictest. from manual page, it seems used to calculate thread latency instead of interrupt latency Would you please let me know if there any kind of command for using it to check interrupt latency ? thanks for your help,
cyclictest V 0.42 Usage: cyclictest <options> -a [NUM] --affinity run thread #N on processor #N, if possible with NUM pin all threads to the processor NUM -b USEC --breaktrace=USEC send break trace command when latency > USEC -B --preemptirqs both preempt and irqsoff tracing (used with -b) -c CLOCK --clock=CLOCK select clock 0 = CLOCK_MONOTONIC (default) 1 = CLOCK_REALTIME -C --context context switch tracing (used with -b) -d DIST --distance=DIST distance of thread intervals in us default=500 -E --event event tracing (used with -b) -f --ftrace function trace (when -b is active) -i INTV --interval=INTV base interval of thread in us default=1000 -I --irqsoff Irqsoff tracing (used with -b) -l LOOPS --loops=LOOPS number of loops: default=0(endless) -m --mlockall lock current and future memory allocations -n --nanosleep use clock_nanosleep -N --nsecs print results in ns instead of ms (default ms) -o RED --oscope=RED oscilloscope mode, reduce verbose output by RED -O TOPT --traceopt=TOPT trace option -p PRIO --prio=PRIO priority of highest prio thread -P --preemptoff Preempt off tracing (used with -b) -q --quiet print only a summary on exit -r --relative use relative timer instead of absolute -s --system use sys_nanosleep and sys_setitimer -T TRACE --tracer=TRACER set tracing function configured tracers: unavailable (debugfs not mounted) -t --threads one thread per available processor -t [NUM] --threads=NUM number of threads: without NUM, threads = max_cpus without -t default = 1 -v --verbose output values on stdout for statistics format: n:c:v n=tasknum c=count v=value in us -D --duration=t specify a length for the test run default is in seconds, but 'm', 'h', or 'd' maybe add ed to modify value to minutes, hours or days -h --histogram=US dump a latency histogram to stdout after the run US is the max time to be be tracked in microseconds -w --wakeup task wakeup tracing (used with -b) -W --wakeuprt rt task wakeup tracing (used with -b)