This patch moves away from using M5_ATTR_OVERRIDE and the m5::hashmap
(and similar) abstractions, as these are no longer needed with gcc 4.7
and clang 3.1 as minimum compiler versions.
Event auto-serialization no longer in use and has been broken ever
since the introduction of PDES support almost two years
ago. Additionally, serializing the individual event queues is
undesirable since it exposes the thread structure of the
simulator. What this means in practice is that the number of threads
in the simulator must be the same when taking a checkpoint and when
loading the checkpoint.
This changeset removes support for the AutoSerialize event flag and
the associated serialization code.
Events expected to be unserialized using an event-specific
unserializeEvent call. This call was never actually used, which meant
the events relying on it never got unserialized (or scheduled after
unserialization).
Instead of relying on a custom call, we now use the normal
serialization code again. In order to schedule the event correctly,
the parrent object is expected to use the
EventQueue::checkpointReschedule() call. This happens automatically
for events that are serialized using the AutoSerialize mechanism.
Objects that are can be serialized are supposed to inherit from the
Serializable class. This class is meant to provide a unified API for
such objects. However, so far it has mainly been used by SimObjects
due to some fundamental design limitations. This changeset redesigns
to the serialization interface to make it more generic and hide the
underlying checkpoint storage. Specifically:
* Add a set of APIs to serialize into a subsection of the current
object. Previously, objects that needed this functionality would
use ad-hoc solutions using nameOut() and section name
generation. In the new world, an object that implements the
interface has the methods serializeSection() and
unserializeSection() that serialize into a named /subsection/ of
the current object. Calling serialize() serializes an object into
the current section.
* Move the name() method from Serializable to SimObject as it is no
longer needed for serialization. The fully qualified section name
is generated by the main serialization code on the fly as objects
serialize sub-objects.
* Add a scoped ScopedCheckpointSection helper class. Some objects
need to serialize data structures, that are not deriving from
Serializable, into subsections. Previously, this was done using
nameOut() and manual section name generation. To simplify this,
this changeset introduces a ScopedCheckpointSection() helper
class. When this class is instantiated, it adds a new /subsection/
and subsequent serialization calls during the lifetime of this
helper class happen inside this section (or a subsection in case
of nested sections).
* The serialize() call is now const which prevents accidental state
manipulation during serialization. Objects that rely on modifying
state can use the serializeOld() call instead. The default
implementation simply calls serialize(). Note: The old-style calls
need to be explicitly called using the
serializeOld()/serializeSectionOld() style APIs. These are used by
default when serializing SimObjects.
* Both the input and output checkpoints now use their own named
types. This hides underlying checkpoint implementation from
objects that need checkpointing and makes it easier to change the
underlying checkpoint storage code.
We need the ability to lock event queues to enable device accesses
across threads. The serviceOne() method now takes a service lock prior
to handling a new event. By locking an event queue, a different
thread/eq can effectively execute in the context of the locked event
queue. To simplify temporary event queue migrations, this changeset
introduces the EventQueue::ScopedMigration class that unlocks the
current event queue, locks a new event queue, and updates the current
event queue variable.
In order to prevent deadlocks, event queues need to be released when
waiting on barriers. This is implemented using the
EventQueue::ScopedRelease class. An instance of this class is, for
example, used in the BaseGlobalEvent class to release the event queue
when waiting on the synchronization barrier.
The intended use for this functionality is when devices need to be
accessed across thread boundaries. For example, when fast-forwarding,
it might be useful to run devices and CPUs in separate threads. In
such a case, the CPU locks the device queue whenever it needs to
perform IO. This functionality is primarily intended for KVM.
Note: Migrating between event queues can lead to non-deterministic
timing. Use with extreme care!
--HG--
extra : rebase_source : 23e3a741a1fd73861d1339782dbbe1bc76285315
2014-04-03 11:22:49 +02:00
Steve Reinhardt ext:(%2C%20Nilay%20Vaish%20%3Cnilay%40cs.wisc.edu%3E%2C%20Ali%20Saidi%20%3CAli.Saidi%40ARM.com%3E)
This patch adds support for simulating with multiple threads, each of
which operates on an event queue. Each sim object specifies which eventq
is would like to be on. A custom barrier implementation is being added
using which eventqs synchronize.
The patch was tested in two different configurations:
1. ruby_network_test.py: in this simulation L1 cache controllers receive
requests from the cpu. The requests are replied to immediately without
any communication taking place with any other level.
2. twosys-tsunami-simple-atomic: this configuration simulates a client-server
system which are connected by an ethernet link.
We still lack the ability to communicate using message buffers or ports. But
other things like simulation start and end, synchronizing after every quantum
are working.
Committed by: Nilay Vaish
This patch adds a _curTick variable to an eventq. This variable is updated
whenever an event is serviced in function serviceOne(), or all events upto
a particular time are processed in function serviceEvents(). This change
helps when there are eventqs that do not make use of curTick for scheduling
events.
This patch adds a function for replacing the event at the head of the queue
with another event. This helps in running a different set of events. Events
already scheduled can processed by replacing the original head event back.
This function has been specifically added to support cache warmup and
cooldown required for creating and restoring checkpoints.
--HG--
extra : rebase_source : ed6e2905720b6bfdefd020fab76235ccf33d28d1
At the same time, rename the trace flags to debug flags since they
have broader usage than simply tracing. This means that
--trace-flags is now --debug-flags and --trace-help is now --debug-help
- Make the initialized flag always available, not just in debug mode.
- Make the Initialized flag actually use several bits so it is very
unlikely that something that's uninitialized accidentally looks
initialized.
- Add an initialized() function that tells you if the current event is
indeed initialized.
- Clear the flags on delete so it can't be accidentally thought of as
initialized.
- Fix getFlags assert statement. "How did this ever work?"
Since I never implemented a proper solution, put it back to something that
at least works for now. Once I add more event queues, I'll have to really
fix this though
Since the early days of M5, an event needed to know which event queue
it was on, and that data was required at the time of construction of
the event object. In the future parallelized M5, this sort of
requirement does not work well since the proper event queue will not
always be known at the time of construction of an event. Now, events
are created, and the EventQueue itself has the schedule function,
e.g. eventq->schedule(event, when). To simplify the syntax, I created
a class called EventManager which holds a pointer to an EventQueue and
provides the schedule interface that is a proxy for the EventQueue.
The intent is that objects that frequently schedule events can be
derived from EventManager and then they have the schedule interface.
SimObject and Port are examples of objects that will become
EventManagers. The end result is that any SimObject can just call
schedule(event, when) and it will just call that SimObject's
eventq->schedule function. Of course, some objects may have more than
one EventQueue, so this interface might not be perfect for those, but
they should be relatively few.
The status quo is preferred since it is less likely that people will
rely on LIFO than FIFO, and when we move to a parallelized M5, no
ordering between events of the same time/priority will be guaranteed.
linked list sorted by time and priority. For things of the same time
and priority, a second, circularly linked list maintains the data
structure. Events of the same time and priority are now inserted in
FIFO order instead of LIFO order. This dramatically improves the
performance of systems that schedule multiple events at the same time.
The FIFO order version is not preferred to LIFO (because it may cause
people to rely on it), but I'm going to commit it anyway and
immediately commit the preferred LIFO version on top.
directly configured by python. Move stuff from root.(cc|hh) to
core.(cc|hh) since it really belogs there now.
In the process, simplify how ticks are used in the python code.
--HG--
extra : convert_revision : cf82ee1ea20f9343924f30bacc2a38d4edee8df3
User script now invokes initialization and
simulation loop after building configuration.
These functions are exported from C++ to Python
using SWIG.
SConstruct:
Set up SWIG builder & scanner.
Set up symlinking of source files into build directory
(by not disabling the default behavior).
configs/test/test.py:
Rewrite to use new script-driven interface.
Include a sample option.
src/SConscript:
Set up symlinking of source files into build directory
(by not disabling the default behavior).
Add SWIG-generated main_wrap.cc to source list.
src/arch/SConscript:
Set up symlinking of source files into build directory
(by not disabling the default behavior).
src/arch/alpha/ev5.cc:
src/arch/alpha/isa/decoder.isa:
src/cpu/o3/alpha_cpu_impl.hh:
src/cpu/trace/opt_cpu.cc:
src/cpu/trace/trace_cpu.cc:
src/sim/pseudo_inst.cc:
src/sim/root.cc:
src/sim/serialize.cc:
src/sim/syscall_emul.cc:
SimExit() is now exitSimLoop().
src/cpu/base.cc:
SimExitEvent is now SimLoopExitEvent
src/python/SConscript:
Add SWIG build command for main.i.
Use python/m5 in build dir as source for zip archive...
easy now with file duplication enabled.
src/python/m5/__init__.py:
- Move copyright notice back to C++ so we can print
it right away, even for interactive sessions.
- Get rid of argument parsing code; just provide default
option descriptors for user script to call optparse with.
- Don't clutter m5 namespace by sucking in all of m5.config
and m5.objects.
- Move instantiate() function here from config.py.
src/python/m5/config.py:
- Move instantiate() function to __init__.py.
- Param.Foo deferred type lookups must use m5.objects
namespace now (not m5).
src/python/m5/objects/AlphaConsole.py:
src/python/m5/objects/AlphaFullCPU.py:
src/python/m5/objects/AlphaTLB.py:
src/python/m5/objects/BadDevice.py:
src/python/m5/objects/BaseCPU.py:
src/python/m5/objects/BaseCache.py:
src/python/m5/objects/Bridge.py:
src/python/m5/objects/Bus.py:
src/python/m5/objects/CoherenceProtocol.py:
src/python/m5/objects/Device.py:
src/python/m5/objects/DiskImage.py:
src/python/m5/objects/Ethernet.py:
src/python/m5/objects/Ide.py:
src/python/m5/objects/IntrControl.py:
src/python/m5/objects/MemObject.py:
src/python/m5/objects/MemTest.py:
src/python/m5/objects/Pci.py:
src/python/m5/objects/PhysicalMemory.py:
src/python/m5/objects/Platform.py:
src/python/m5/objects/Process.py:
src/python/m5/objects/Repl.py:
src/python/m5/objects/Root.py:
src/python/m5/objects/SimConsole.py:
src/python/m5/objects/SimpleDisk.py:
src/python/m5/objects/System.py:
src/python/m5/objects/Tsunami.py:
src/python/m5/objects/Uart.py:
Fix up imports (m5 namespace no longer includes m5.config).
src/sim/eventq.cc:
src/sim/eventq.hh:
Support for Python-called simulate() function:
- Use IsExitEvent flag to signal events that want
to exit the simulation loop gracefully (instead of
calling exit() to terminate the process).
- Modify interface to hand exit event object back to
caller so it can be inspected for cause.
src/sim/host.hh:
Add MaxTick constant.
src/sim/main.cc:
Move copyright notice back to C++ so we can print
it right away, even for interactive sessions.
Use PYTHONPATH environment var to set module path
(instead of clunky code injection method).
Move main control from here into Python:
- Separate initialization code and simulation loop
into separate functions callable from Python.
- Make Python interpreter invocation more pure (more
like directly invoking interpreter).
Add -i and -p flags (only options on binary itself;
other options processed by Python).
Import readline package when using interactive mode.
src/sim/sim_events.cc:
SimExitEvent is now SimLoopExitEvent, and uses
IsSimExit flag to terminate loop (instead of
exiting simulator process).
src/sim/sim_events.hh:
SimExitEvent is now SimLoopExitEvent, and uses
IsSimExit flag to terminate loop (instead of
exiting simulator process).
Get rid of a few unused constructors.
src/sim/sim_exit.hh:
SimExit() is now exitSimLoop().
Get rid of unused functions.
Add comments.
--HG--
extra : convert_revision : 280b0d671516b25545a6f24cefa64a68319ff3d4
