Schedulability Experiments Framewok

Dependencies & Compilation

Packages

To compile and run the experiments, the following standard packages are required:

• Python 2.7
• Python NumPy Library
• Python SciPy LIbrary
• GNU Make (make)
• SWIG 3.0 (swig)
• GNU C++ compiler (g++)
• GNU Multiple Precision Arithmetic Library (libgmp)

  Installing a Linear Program Solver

  A linear program solver is also required. IBM CPLEX is supported. IBM CPLEX is commercial software, but free academic licenses are available.

We test the file cplex_studio12.7.1.linux-x86-64.bin on Ubuntu 14.04 (x86_64). The filename may change when newer versions of CPLEX are released. To install CPLEX, execute the following commands

$ chmod +x cplex_studio12.7.1.linux-x86-64.bin
# ./cplex_studio12.7.1.linux-x86-64.bin

Compiling SchedCAT

SchedCAT provides lots of schedulability test utilities. After set up and update the SchedCAT submodule, you can compile it by running

$ cd lib/schedcat
$ make
$ cd ../../

Note: The makefiles try to automatically locate an installation of CPLEX. In some cases this procedure may fail and the build process terminates with the error “No LP Solver available”. If this happens, the CPLEX path must be manually configured with the following command:

$ export CPLEX_PATH=<your_CPLEX_path_here>

For instance, the above tested CPLEX is installed with default options, and the path is configured as follows:

$ export CPLEX_PATH=/opt/ibm/ILOG/CPLEX_Studio1271

In addition, some installations of CPLEX may not create symbolic links of the CPLEX static libraries into the /usr/lib/ directory. Those links are created on the teste machine with the following commands:

# ln -s <your_CPLEX_path_here>/concert/lib/x86-64_linux/static_pic/libconcert.a /usr/lib/libconcert.a
# ln -s <your_CPLEX_path_here>/cplex/lib/x86-64_linux/static_pic/libcplex.a /usr/lib/libcplex.a 
# ln -s <your_CPLEX_path_here>/cplex/lib/x86-64_linux/static_pic/libilocplex.a /usr/lib/libilocplex.a 

Schedulability Experiments and Configurations

Before launching the experiment, it is necessary to set an environmental variable for SchedCAT:

export PYTHONPATH=$PYTHONPATH:./lib/schedcat
export CPLEX_PATH=/opt/ibm/ILOG/CPLEX_Studio1271

A configuration represents all the settings for the task set generators and defines the experiment to be performed.

The directory ./confs contains a .conf file for each configuration tested in the experiments. The name of each .conf file contains key-value pairs with the values for (most of) the parameters.

As example, a configuration file named

./confs/read_len/rn=10_wl=100_u=75_c=20_wn=10.conf

corresponds to a configuration

• 10 readers (rn=10)
• 10 writers (wn=10)
• 20 cores (c=20)
• 0.75 task set utilization (u=75)
• write request length of 10 (wl=10)

The following command runs the schedulability experiment for a specific configuration:

$ python -m exp -f ./confs/<configuration file>

For example

$ python -m exp -f ./confs/unit_test.conf
$ python -m exp -f ./confs/read_len/rn=10_wl=100_u=75_c=20_wn=10.conf

The experiment results are written to a output file in ./output

Safety-Aware Scheduling Contest Reproduction

For the contest case “安全感知任务调度”, use the cleaned reproduction entry below. It preserves the original SchedCAT/Python 2.7 experiment stack while making the Fig. 4 style syscall-auditing experiment parameterized and reproducible.

git submodule update --init --recursive
source setpath.sh
cd lib/schedcat && make && cd ../../
python rta/safety_aware_sched.py --experiment utilization --samples 1000

Useful variants:

python rta/safety_aware_sched.py --experiment syscall_count --samples 1000
python rta/safety_aware_sched.py --experiment cpu_count --samples 1000
python rta/safety_aware_sched.py --experiment all --samples 1000

Outputs are written to output/safety_aware_sched/ and include the full configuration, runtime environment, schedulability ratios, and NoDrop event residence-time statistics. The feature design and test plan for the contest submission are in docs/feature_design.md and docs/test_plan.md.