gem5 - gem5

Age	Commit message (Collapse)	Author
2014-09-09	sim: Fix resource leak in BaseGlobalEvent	Andreas Sandberg
	Static analysis revealed that BaseGlobalEvent::barrier was never deallocated. This changeset solves this leak by making the barrier allocation a part of the BaseGlobalEvent instead of storing a pointer to a separate heap-allocated barrier.
2014-04-03	sim: Add the ability to lock and migrate between event queues	Andreas Sandberg
	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
2013-11-25	sim: simulate with multiple threads and event queues	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