MicroEarthquake reproduces flaky bugs by fuzzing process scheduling with sched_setattr(2).

$ (cd microearthquake; python3 native_build.py)

On Terminal 1:

$ (cd /somewhere; mvn test)

On Terminal 2:

$ ./bin/microearthquake pid $TERMINAL1_MVN_PID

Notes:

• Requires CAP_SYS_NICE.
• subprocesses and LWPs (i.e.,threads) are also fuzzed.

Using Dirichlet distribution, MicroEarthquake finds the randomized utilization sequence $u_i$ ($0 <= i < NTASKS$) that satisfies $\sum u_i = NCPU$.

Then MicroEarthquake determines actual parameters that almost satisfy $WCET_i / P_i = u_i$.

See sched-deadline.txt.

We still need much more improvement.

• YARN-{1978, 4168, 4543, 4548, 4556}
• etcd {#4006, #4039}
• ..

• FOSDEM (January 30-31, 2016, Brussels)

• Earthquake: a programmable fuzzy scheduler for testing distributed systems

MicroEarthquake is planned to be rewritten in Go and merged to Earthquake;

Even after that, MicroEarthquake may continue as a lightweight version of Earthquake.

After running MicroEarthquake many times, sched_setattr(2) can fail with EBUSY. This seems to be a bug of kernel; I'm looking into this.