import os, select
import virt_utils, virt_vm, aexpect
class scheduler:
"""
A scheduler that manages several parallel test execution pipelines on a
single host.
"""
def __init__(self, tests, num_workers, total_cpus, total_mem, bindir):
"""
Initialize the class.
@param tests: A list of test dictionaries.
@param num_workers: The number of workers (pipelines).
@param total_cpus: The total number of CPUs to dedicate to tests.
@param total_mem: The total amount of memory to dedicate to tests.
@param bindir: The directory where environment files reside.
"""
self.tests = tests
self.num_workers = num_workers
self.total_cpus = total_cpus
self.total_mem = total_mem
self.bindir = bindir
# Pipes -- s stands for scheduler, w stands for worker
self.s2w = [os.pipe() for i in range(num_workers)]
self.w2s = [os.pipe() for i in range(num_workers)]
self.s2w_r = [os.fdopen(r, "r", 0) for r, w in self.s2w]
self.s2w_w = [os.fdopen(w, "w", 0) for r, w in self.s2w]
self.w2s_r = [os.fdopen(r, "r", 0) for r, w in self.w2s]
self.w2s_w = [os.fdopen(w, "w", 0) for r, w in self.w2s]
# "Personal" worker dicts contain modifications that are applied
# specifically to each worker. For example, each worker must use a
# different environment file and a different MAC address pool.
self.worker_dicts = [{"env": "env%d" % i} for i in range(num_workers)]
def worker(self, index, run_test_func):
"""
The worker function.
Waits for commands from the scheduler and processes them.
@param index: The index of this worker (in the range 0..num_workers-1).
@param run_test_func: A function to be called to run a test
(e.g. job.run_test).
"""
r = self.s2w_r[index]
w = self.w2s_w[index]
self_dict = self.worker_dicts[index]
# Inform the scheduler this worker is ready
w.write("ready\n")
while True:
cmd = r.readline().split()
if not cmd:
continue
# The scheduler wants this worker to run a test
if cmd[0] == "run":
test_index = int(cmd[1])
test = self.tests[test_index].copy()
test.update(self_dict)
test_iterations = int(test.get("iterations", 1))
status = run_test_func("kvm", params=test,
tag=test.get("shortname"),
iterations=test_iterations)
w.write("done %s %s\n" % (test_index, status))
w.write("ready\n")
# The scheduler wants this worker to free its used resources
elif cmd[0] == "cleanup":
env_filename = os.path.join(self.bindir, self_dict["env"])
env = virt_utils.Env(env_filename)
for obj in env.values():
if isinstance(obj, virt_vm.VM):
obj.destroy()
elif isinstance(obj, aexpect.Spawn):
obj.close()
env.save()
w.write("cleanup_done\n")
w.write("ready\n")
# There's no more work for this worker
elif cmd[0] == "terminate":
break
def scheduler(self):
"""
The scheduler function.
Sends commands to workers, telling them to run tests, clean up or
terminate execution.
"""
idle_workers = []
closing_workers = []
test_status = ["waiting"] * len(self.tests)
test_worker = [None] * len(self.tests)
used_cpus = [0] * self.num_workers
used_mem = [0] * self.num_workers
while True:
# Wait for a message from a worker
r, w, x = select.select(self.w2s_r, [], [])
someone_is_ready = False
for pipe in r:
worker_index = self.w2s_r.index(pipe)
msg = pipe.readline().split()
if not msg:
continue
# A worker is ready -- add it to the idle_workers list
if msg[0] == "ready":
idle_workers.append(worker_index)
someone_is_ready = True
# A worker completed a test
elif msg[0] == "done":
test_index = int(msg[1])
test = self.tests[test_index]
status = int(eval(msg[2]))
test_status[test_index] = ("fail", "pass")[status]
# If the test failed, mark all dependent tests as "failed" too
if not status:
for i, other_test in enumerate(self.tests):
for dep in other_test.get("dep", []):
if dep in test["name"]:
test_status[i] = "fail"
# A worker is done shutting down its VMs and other processes
elif msg[0] == "cleanup_done":
used_cpus[worker_index] = 0
used_mem[worker_index] = 0
closing_workers.remove(worker_index)
if not someone_is_ready:
continue
for worker in idle_workers[:]:
# Find a test for this worker
test_found = False
for i, test in enumerate(self.tests):
# We only want "waiting" tests
if test_status[i] != "waiting":
continue
# Make sure the test isn't assigned to another worker
if test_worker[i] is not None and test_worker[i] != worker:
continue
# Make sure the test's dependencies are satisfied
dependencies_satisfied = True
for dep in test["dep"]:
dependencies = [j for j, t in enumerate(self.tests)
if dep in t["name"]]
bad_status_deps = [j for j in dependencies
if test_status[j] != "pass"]
if bad_status_deps:
dependencies_satisfied = False
break
if not dependencies_satisfied:
continue
# Make sure we have enough resources to run the test
test_used_cpus = int(test.get("used_cpus", 1))
test_used_mem = int(test.get("used_mem", 128))
# First make sure the other workers aren't using too many
# CPUs (not including the workers currently shutting down)
uc = (sum(used_cpus) - used_cpus[worker] -
sum(used_cpus[i] for i in closing_workers))
if uc and uc + test_used_cpus > self.total_cpus:
continue
# ... or too much memory
um = (sum(used_mem) - used_mem[worker] -
sum(used_mem[i] for i in closing_workers))
if um and um + test_used_mem > self.total_mem:
continue
# If we reached this point it means there are, or will
# soon be, enough resources to run the test
test_found = True
# Now check if the test can be run right now, i.e. if the
# other workers, including the ones currently shutting
# down, aren't using too many CPUs
uc = (sum(used_cpus) - used_cpus[worker])
if uc and uc + test_used_cpus > self.total_cpus:
continue
# ... or too much memory
um = (sum(used_mem) - used_mem[worker])
if um and um + test_used_mem > self.total_mem:
continue
# Everything is OK -- run the test
test_status[i] = "running"
test_worker[i] = worker
idle_workers.remove(worker)
# Update used_cpus and used_mem
used_cpus[worker] = test_used_cpus
used_mem[worker] = test_used_mem
# Assign all related tests to this worker
for j, other_test in enumerate(self.tests):
for other_dep in other_test["dep"]:
# All tests that depend on this test
if other_dep in test["name"]:
test_worker[j] = worker
break
# ... and all tests that share a dependency
# with this test
for dep in test["dep"]:
if dep in other_dep or other_dep in dep:
test_worker[j] = worker
break
# Tell the worker to run the test
self.s2w_w[worker].write("run %s\n" % i)
break
# If there won't be any tests for this worker to run soon, tell
# the worker to free its used resources
if not test_found and (used_cpus[worker] or used_mem[worker]):
self.s2w_w[worker].write("cleanup\n")
idle_workers.remove(worker)
closing_workers.append(worker)
# If there are no more new tests to run, terminate the workers and
# the scheduler
if len(idle_workers) == self.num_workers:
for worker in idle_workers:
self.s2w_w[worker].write("terminate\n")
break