Re: [RFC] rt-app: add script to generate small task workloads

On 22 October 2014 03:39, pi-cheng.chen pi-cheng.chen@linaro.org wrote:

Some examples to use the script to generate small tasks workloads:

1. to generate a workload with 4 threads, 10% load and 30ms period

$ ./small_task_gen -t 4 -l 10 -p 3

The period unit seems to be 10ms which is quite long, please use a more fine grained value; at least ms or even us

2. to generate a workload with 3 threads, 15% load and random tick-aligned period

$ ./small_task_gen -t 3 -l 15 -r --aligned

3. to generate a workload with 5 threads, 20% load and random non-tick-aligned period

$ ./small_task_gen -t 5 -l 20 -r --unaligned

What about a defined but unaligned period ? it doesn't seems to be possible

---

doc/examples/small_task_gen | 117 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 117 insertions(+) create mode 100755 doc/examples/small_task_gen

diff --git a/doc/examples/small_task_gen b/doc/examples/small_task_gen new file mode 100755 index 0000000..ba74753 --- /dev/null +++ b/doc/examples/small_task_gen @@ -0,0 +1,117 @@ +#!/usr/bin/env python

+import sys +import getopt +import random

+outfile = "small_tasks.json" +tasks = None +loading = None +period = None +randomized = None +aligned = None

+def usage():

• print "Usage:"
• print sys.argv[0] + " -t <number of tasks>"
• print "\t\t -l <percentage of task loading> (1 - 100)"
• print "\t\t -p <fixed period in ms>"
• print "\t\t -r [--aligned | --unaligned] (randomize periods of tasks)"
• print "\t\t -o <output JSON file name> (default: small_tasks.json)"
• return

+def parse_options():

• global outfile
• global tasks
• global loading
• global period
• global randomized
• global aligned
• try:

•    opts, args = getopt.getopt(sys.argv[1:], "t:l:o:p:rh",
  

•                               ["aligned", "unaligned"])
  

• except getopt.GetoptError:

•    usage()
  

•    sys.exit(2)
  

• for o, a in opts:

•    if o == "-t":
  

•        tasks = int(a)
  

•        print "number of tasks: %d" % tasks
  

•    if o == "-l":
  

•        loading = int(a)
  

•        print "task loading: %d" % loading
  

•    if o == "-o":
  

•        outfile = a;
  

•        print "output workload JSON file: " + outfile
  

•    if o == "-p":
  

•        period = int(a)
  

•        print "period of tasks: %d" % period
  

•    if o == "-r":
  

•        randomized = True
  

•        print "randomized: %r" % randomized
  

•    if o == "--aligned":
  

•        if aligned == False:
  

•            usage()
  

•            sys.exit(2)
  

•        aligned = True
  

•        print "aligned: %r" % aligned
  

•    if o in "--unaligned":
  

•        if aligned == True:
  

•            usage()
  

•            sys.exit(2)
  

•        aligned = False
  

•        print "aligned: %r" % aligned
  

•    if o == "-h":
  

•        usage()
  

•        sys.exit(2)
  

• if not period is None and not randomized is None:

•    usage()
  

•    sys.exit(2)
  

• if tasks is None or (period is None and randomized is None):

•    usage()
  

•    sys.exit(2)
  

• return

+def generate_workload():

• try:

•    f = open(outfile, "w")
  

• except IOError:

•    print "WARN: Unable to open " + infile
  

•    sys.exit(2)
  

• f.write("{\n")
• f.write("\t"tasks" : {\n")
• for i in range(0, tasks):

•    if randomized is None:
  

•        period_ns = period * 1000
  

•    else:
  

•        period_ns = random.randrange(1, 6) * 10000 # random tick-aligned period from 10ms~50ms
  

the [10:50]ms range for the random period is quite arbitrary, we should be able to specify a range for the random value

•        if aligned == False: # add a period offset randomly from 1 of [300, 500, 700]
  

•            period_ns += (3000, 5000, 7000)[random.randrange(0, 3)]
  

yous should not specify a restricted list of random offset

•    run_ns = period_ns * loading / 100
  

•    f.write("\t\t\"thread%d\" : {\n" % i)
  

•    f.write("\t\t\t\"loop\" : -1,\n")
  

•    f.write("\t\t\t\"run\" : %d,\n" % run_ns)
  

•    f.write("\t\t\t\"timer\" : { \"ref\" : \"tick\", \"period\" : %d },\n" % period_ns)
  

you should use a different timer id for each task instead of sharing the tick timer between tasks

•    f.write("\t\t},\n")
  

• f.write("\t},\n")
• f.write("}\n")

As discussed, I still think that it's not straight forward to understand what the script is doing or to reuse it for another use case. But I haven't found a better way so far. IMO, the use of a model that is then modifed according parameters is a bit easier to use or reuse but i also agree that it's more complex to parse and modify a model than creating a json file from scratch

Regards, Vincent

• return

+if __name__ == '__main__':

• parse_options()
• generate_workload()

-- 1.9.1