Priyanka, For some reason all of us that work on rt-tests were busy last week. I'll apply these patches and try out cyclicload this week. Clark On Mon, 6 Aug 2012 04:00:15 +0000 Jain Priyanka-B32167 <B32167@xxxxxxxxxxxxx> wrote: > Hi, > > Waiting for the comments on this tool. > > Thanks > Priyanka > > -----Original Message----- > From: Jain Priyanka-B32167 > Sent: Wednesday, August 01, 2012 10:37 AM > To: linux-rt-users@xxxxxxxxxxxxxxx; williams@xxxxxxxxxx; dvhart@xxxxxxxxxxxxxxx > Cc: rostedt@xxxxxxxxxxx; tglx@xxxxxxxxxxxxx; Srivastava Rajan-B34330; Aggrwal Poonam-B10812; Jain Priyanka-B32167 > Subject: [PATCH 1/2][RFC] Add README_cyclicload > > Cyclicload program is designed to simulate load at regular intervals in form of one or two threads. > > Signed-off-by: Priyanka Jain <Priyanka.Jain@xxxxxxxxxxxxx> > --- > src/cyclictest/README_cyclicload | 147 ++++++++++++++++++++++++++++++++++++++ > 1 files changed, 147 insertions(+), 0 deletions(-) create mode 100644 src/cyclictest/README_cyclicload > > diff --git a/src/cyclictest/README_cyclicload b/src/cyclictest/README_cyclicload > new file mode 100644 > index 0000000..f1e99bf > --- /dev/null > +++ b/src/cyclictest/README_cyclicload > @@ -0,0 +1,147 @@ > +DESCRIPTION > +------------- > + > +The cyclicload program is developed above existing cyclictest application. > +It is basically designed to simulate specified load at regular > +intervals in addition to cyclictest functionality. > +It can simulate one or two load threads. > + > + > +Why it is required? > +--------------------- > +It is required to test system performance under a specified load along > +with tracking latency of simulated load thread. > + > + > +Example use case > +-------------------- > +For products like LTE, L2 layer runs in form of two threads. > +-MAC layer thread runs at highest RT priority producing a fixed load at > +regular intervals and -second thread run at lower RT priority or in > +non-rt priority producing some load in each interval depending upon > +availability of CPU. > +Requirement is to test system under this load as well as to track > +latency of highest priority RT thread which is MAC thread in example > +usecase. > + > + > +What does it do? > +------------------ > +It creates one or two load generating thread/s. > +1)load1 thread (timer thread) > +2)load2 thread > +priority, nice value, load % as input via command line > + > +-cyclictest funcationality like latency measurement > + > + > +How does it work > +----------------- > +It uses generate_load loop function to simualte load. > +First it caliberate required loop_count per unit time per CPU. > +It stores this data in some file. > +For subsequent runs, it uses this caliberated data to generate load if > +form of one or two threads . > +It keeps on tracking the latency of RT thread. > +More in Design Overview section. > + > + > +Recommended Settings > +---------------------- > +-First run is recommended to be run with no or least load for accuracy. > +-should be run with sudo or root permission. > +-caliberation routine produces calinerate_ount file in runnign directory. > + If one don't have permission in that dir, path should be changed in > + FILENAME or one can exploit shared memory method. > +-Atleast one thread should be of RT priority. This thread takes priority of > + cyclictest as its priority. > +-cyclictest applcication should be run with SCHED_OTHER policy. > +-recommended to run in quiet mode (-q) in background. > +TODO: add option to take filepath from cmd line > + > + > +Cmd line usage/examples > +------------------------ > +New command line arguments: > + "-x --load_t1 load in percentage for t1 thread\n" > + "-X --load_t2 load in percentage for t2 thread\n" > + "-z --priority_t2 priority of t2 thread\n" > + "-Z --nice_t2 nice value of t2 thread\n" > + > +If both load_t1 and load_t2 are zero, it behaves as default cyclictest > +application > + > +For uniprocessor: > + #sudo ./cyclictest -p 99 -c 1 -d 0 -x 40 -X 30 -q -D 600& > + > +For multiprocessor: > + #sudo ./cyclcitest -p 99 -c 1 -d 0 -x 40 -X 30 -q -D 600 -S& > + > + > + > +Future Enhancements > +------------------- > +Maintain statistics of average load produces. > +invalidate cache in each interval to make it close to actual scenario. > +can be scalable to produce n number of load threads. > + > + > +Design Overview > +-------------- > +--------------- > + > +The logic to simulate load has been added above existing cyclictest application. > + > +Threads > +-------- > +cyclicload : main process > +-------------------------- > +-parse input arguments. > + > +-for first run : create caliberate thread. > + store caliberated count in caliberate_count file -for subsequent runs: > + read caliberated count from file and use that count to simulate defined load. > + > +-create t load1threads (t depending on cmdlime args, for smp system = > +num of cores, one thread per core) > + > +-update stats periodically while !shutdown -print stats periodically > +depending on cmdline args while !shutdown > + > + > +caliberate thread > +------------------ > +-is created only once for the first run of cyclicload -run at highest > +RT priority. > +-affine itself turn by turn to each cpu. (for all cpus for multicore > +system) -caliberate count per unit (ms by default) per cpu -store per > +cpu data in caliberate_count_array -recommended to be run with no or > +least load. > + > + > +load1 thread(timer thread) > +--------------------------- > +-run at priority parsed in main routine -recommended to run at highest > +RT priority -creates load2_thread (optional only if on load2 is > +nonzero) -calculate number of loops to execute to generate defined load > +by > + using caliberate_count_array and load percentage parsed in main > +routine -reduced interval = interval(window) - duration for load_t1 > +-while loop until !shutdown > + -generate load_t1 load > + -sleep for reduced interval > + -calculate latency (cosumes around 1%-2% cpu) > + -discard off remaining load if window expires > + -set next_window_started flag to 1 > + -signal load2_thread about next window > +-overhead: consumes 1-2% cpu for latency maintainenance, etc -variation > +in produced load : 0%-2% of full cpu utilization > + > + > +load2_thread > +------------ > +generate load_t2 load > +wait for next window to start > +if window expires before generate load_t2 finishes, > + discard off remaining load > + restart generate load_t2 load > +variation in produced load : 0%-1% of full cpu utilization > -- > 1.7.4.1 > > >
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