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config: Move CPU handover logic to m5.switchCpus()

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CPU switching consists of the following steps:
 1. Drain the system
 2. Switch out old CPUs (cpu.switchOut())
 3. Change the system timing mode to the mode the new CPUs require
 4. Flush caches if switching to hardware virtualization
 5. Inform new CPUs of the handover (cpu.takeOverFrom())
 6. Resume the system

m5.switchCpus() previously only did step 2 & 5. Since information
about the new processors' memory system requirements is now exposed,
do all of the steps above.

This patch adds automatic memory system switching and flush (if
needed) to switchCpus(). Additionally, it adds optional draining to
switchCpus(). This has the following implications:

* changeToTiming and changeToAtomic are no longer needed, so they have
  been removed.

* changeMemoryMode is only used internally, so it is has been renamed
  to be private.

* switchCpus requires a reference to the system containing the CPUs as
  its first parameter.

WARNING: This changeset breaks compatibility with existing
configuration scripts since it changes the signature of
m5.switchCpus().
This commit is contained in:
Andreas Sandberg 2013-02-15 17:40:08 -05:00
parent e9f66dceac
commit e5dca84c3f
3 changed files with 60 additions and 34 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
configs/common/Simulation.py
View file

@ -242,10 +242,7 @@ def repeatSwitch(testsys, repeat_switch_cpu_list, maxtick, switch_freq):
if exit_cause != "simulate() limit reached":
return exit_event
print "draining the system"
m5.drain(testsys)
m5.switchCpus(repeat_switch_cpu_list)
m5.resume(testsys)
m5.switchCpus(testsys, repeat_switch_cpu_list)
tmp_cpu_list = []
for old_cpu, new_cpu in repeat_switch_cpu_list:
@ -436,15 +433,7 @@ def run(options, root, testsys, cpu_class):
exit_event = m5.simulate(10000)
print "Switched CPUS @ tick %s" % (m5.curTick())
# when you change to Timing (or Atomic), you halt the system
# given as argument. When you are finished with the system
# changes (including switchCpus), you must resume the system
# manually. You DON'T need to resume after just switching
# CPUs if you haven't changed anything on the system level.
m5.changeToTiming(testsys)
m5.switchCpus(switch_cpu_list)
m5.resume(testsys)
m5.switchCpus(testsys, switch_cpu_list)
if options.standard_switch:
print "Switch at instruction count:%d" % \
@ -458,9 +447,7 @@ def run(options, root, testsys, cpu_class):
print "Switching CPUS @ tick %s" % (m5.curTick())
print "Simulation ends instruction count:%d" % \
(testsys.switch_cpus_1[0].max_insts_any_thread)
m5.drain(testsys)
m5.switchCpus(switch_cpu_list1)
m5.resume(testsys)
m5.switchCpus(testsys, switch_cpu_list1)
# If we're taking and restoring checkpoints, use checkpoint_dir
# option only for finding the checkpoints to restore from. This

63
src/python/m5/simulate.py
View file

@ -60,6 +60,11 @@ from util import attrdict
# define a MaxTick parameter
MaxTick = 2**63 - 1
_memory_modes = {
"atomic" : objects.params.atomic,
"timing" : objects.params.timing,
}
# The final hook to generate .ini files. Called from the user script
# once the config is built.
def instantiate(ckpt_dir=None):
@ -202,7 +207,7 @@ def checkpoint(dir):
internal.core.serializeAll(dir)
resume(root)
def changeMemoryMode(system, mode):
def _changeMemoryMode(system, mode):
if not isinstance(system, (objects.Root, objects.System)):
raise TypeError, "Parameter of type '%s'. Must be type %s or %s." % \
(type(system), objects.Root, objects.System)
@ -212,15 +217,26 @@ def changeMemoryMode(system, mode):
else:
print "System already in target mode. Memory mode unchanged."
def changeToAtomic(system, **kwargs):
print "Changing memory mode to atomic"
changeMemoryMode(system, objects.params.atomic, **kwargs)
def switchCpus(system, cpuList, do_drain=True):
"""Switch CPUs in a system.
def changeToTiming(system, **kwargs):
print "Changing memory mode to timing"
changeMemoryMode(system, objects.params.timing, **kwargs)
By default, this method drains and resumes the system. This
behavior can be disabled by setting the keyword argument
'do_drain' to false, which might be desirable if multiple
operations requiring a drained system are going to be performed in
sequence.
def switchCpus(cpuList):
Note: This method may switch the memory mode of the system if that
is required by the CPUs. It may also flush all caches in the
system.
Arguments:
system -- Simulated system.
cpuList -- (old_cpu, new_cpu) tuples
Keyword Arguments:
do_drain -- Perform a drain/resume of the system when switching.
"""
print "switching cpus"
if not isinstance(cpuList, list):
raise RuntimeError, "Must pass a list to this function"
@ -228,7 +244,10 @@ def switchCpus(cpuList):
if not isinstance(item, tuple) or len(item) != 2:
raise RuntimeError, "List must have tuples of (oldCPU,newCPU)"
old_cpu_set = set([old_cpu for old_cpu, new_cpu in cpuList])
old_cpus = [old_cpu for old_cpu, new_cpu in cpuList]
new_cpus = [new_cpu for old_cpu, new_cpu in cpuList]
old_cpu_set = set(old_cpus)
memory_mode_name = new_cpus[0].memory_mode()
for old_cpu, new_cpu in cpuList:
if not isinstance(old_cpu, objects.BaseCPU):
raise TypeError, "%s is not of type BaseCPU" % old_cpu
@ -240,15 +259,41 @@ def switchCpus(cpuList):
if not new_cpu.switchedOut():
raise RuntimeError, \
"New CPU (%s) is already active." % (new_cpu,)
if not new_cpu.support_take_over():
raise RuntimeError, \
"New CPU (%s) does not support CPU handover." % (old_cpu,)
if new_cpu.memory_mode() != memory_mode_name:
raise RuntimeError, \
"%s and %s require different memory modes." % (new_cpu,
new_cpus[0])
if old_cpu.switchedOut():
raise RuntimeError, \
"Old CPU (%s) is inactive." % (new_cpu,)
if not old_cpu.support_take_over():
raise RuntimeError, \
"Old CPU (%s) does not support CPU handover." % (old_cpu,)
try:
memory_mode = _memory_modes[memory_mode_name]
except KeyError:
raise RuntimeError, "Invalid memory mode (%s)" % memory_mode_name
if do_drain:
drain(system)
# Now all of the CPUs are ready to be switched out
for old_cpu, new_cpu in cpuList:
old_cpu.switchOut()
# Change the memory mode if required. We check if this is needed
# to avoid printing a warning if no switch was performed.
if system.getMemoryMode() != memory_mode:
_changeMemoryMode(system, memory_mode)
for old_cpu, new_cpu in cpuList:
new_cpu.takeOverFrom(old_cpu)
if do_drain:
resume(system)
from internal.core import disableAllListeners

12
tests/configs/switcheroo.py
View file

@ -40,12 +40,6 @@ from m5.objects import *
m5.util.addToPath('../configs/common')
from Caches import *
def _memMode(cclass):
if cclass == AtomicSimpleCPU:
return "atomic", m5.objects.params.atomic
else:
return "timing", m5.objects.params.timing
class Sequential:
"""Sequential CPU switcher.
@ -104,7 +98,7 @@ def run_test(root, switcher=None, freq=1000):
current_cpu = switcher.first()
system = root.system
system.mem_mode = _memMode(type(current_cpu))[0]
system.mem_mode = type(current_cpu).memory_mode()
# instantiate configuration
m5.instantiate()
@ -122,9 +116,9 @@ def run_test(root, switcher=None, freq=1000):
print "Switching CPUs..."
print "Next CPU: %s" % type(next_cpu)
m5.drain(system)
system.setMemoryMode(_memMode(type(next_cpu))[1])
if current_cpu != next_cpu:
m5.switchCpus([ (current_cpu, next_cpu) ])
m5.switchCpus(system, [ (current_cpu, next_cpu) ],
do_drain=False)
else:
print "Source CPU and destination CPU are the same, skipping..."
m5.resume(system)