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path: root/src/mem/simple_mem.cc
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2013-09-18mem: Fix scheduling bug in SimpleMemoryAndreas Hansson
This patch ensures that a dequeue event is not scheduled if the memory controller is waiting for a retry already. Without this check it is possible for the controller to attempt sending something whilst already having one packet that is in retry, thus causing the bus to have an assertion failure.
2013-08-19mem: Add an internal packet queue in SimpleMemoryAndreas Hansson
This patch adds a packet queue in SimpleMemory to avoid using the packet queue in the port (and thus have no involvement in the flow control). The port queue was bound to 100 packets, and as the SimpleMemory is modelling both a controller and an actual RAM, it potentially has a large number of packets in flight. There is currently no limit on the number of packets in the memory controller, but this could easily be added in a follow-on patch. As a result of the added internal storage, the functional access and draining is updated. Some minor cleaning up and renaming has also been done. The memtest regression changes as a result of this patch and the stats will be updated.
2013-02-19mem: Enforce strict use of busFirst- and busLastWordTimeAndreas Hansson
This patch adds a check to ensure that the delay incurred by the bus is not simply disregarded, but accounted for by someone. At this point, all the modules do is to zero it out, and no additional time is spent. This highlights where the bus timing is simply dropped instead of being paid for. As a follow up, the locations identified in this patch should add this additional time to the packets in one way or another. For now it simply acts as a sanity check and highlights where the delay is simply ignored. Since no time is added, all regressions remain the same.
2013-01-08mem: Fix use-after-free bugMitch Hayenga
Running with valgrind I noticed a use after free originating from simple_mem.cc. It looks like this is a known issue and this additional call site was missed in an earlier patch.
2012-11-02mem: fix use after free issue in memories until 4-phase work complete.Ali Saidi
2012-11-02sim: Move the draining interface into a separate base classAndreas Sandberg
This patch moves the draining interface from SimObject to a separate class that can be used by any object needing draining. However, objects not visible to the Python code (i.e., objects not deriving from SimObject) still depend on their parents informing them when to drain. This patch also gets rid of the CountedDrainEvent (which isn't really an event) and replaces it with a DrainManager.
2012-10-15Port: Add protocol-agnostic ports in the port hierarchyAndreas Hansson
This patch adds an additional level of ports in the inheritance hierarchy, separating out the protocol-specific and protocl-agnostic parts. All the functionality related to the binding of ports is now confined to use BaseMaster/BaseSlavePorts, and all the protocol-specific parts stay in the Master/SlavePort. In the future it will be possible to add other protocol-specific implementations. The functions used in the binding of ports, i.e. getMaster/SlavePort now use the base classes, and the index parameter is updated to use the PortID typedef with the symbolic InvalidPortID as the default.
2012-09-18Mem: Add a maximum bandwidth to SimpleMemoryAndreas Hansson
This patch makes a minor addition to the SimpleMemory by enforcing a maximum data rate. The bandwidth is configurable, and a reasonable value (12.8GB/s) has been choosen as the default. The changes do add some complexity to the SimpleMemory, but they should definitely be justifiable as this enables a far more realistic setup using even this simple memory controller. The rate regulation is done for reads and writes combined to reflect the bidirectional data busses used by most (if not all) relevant memories. Moreover, the regulation is done per packet as opposed to long term, as it is the short term data rate (data bus width times frequency) that is the limiting factor. A follow-up patch bumps the stats for the regressions.
2012-07-12Mem: Make SimpleMemory single portedAndreas Hansson
This patch changes the simple memory to have a single slave port rather than a vector port. The simple memory makes no attempts at modelling the contention between multiple ports, and any such multiplexing and demultiplexing could be done in a bus (or crossbar) outside the memory controller. This scenario also matches with the ongoing work on a SimpleDRAM model, which will be a single-ported single-channel controller that can be used in conjunction with a bus (or crossbar) to create a multi-port multi-channel controller. There are only very few regressions that make use of the vector port, and these are all for functional accesses only. To facilitate these cases, memtest and memtest-ruby have been updated to also have a "functional" bus to perform the (de)multiplexing of the functional memory accesses.
2012-07-09Port: Make getAddrRanges constAndreas Hansson
This patch makes getAddrRanges const throughout the code base. There is no reason why it should not be, and making it const prevents adding any unintentional side-effects.
2012-04-06MEM: Enable multiple distributed generalized memoriesAndreas Hansson
This patch removes the assumption on having on single instance of PhysicalMemory, and enables a distributed memory where the individual memories in the system are each responsible for a single contiguous address range. All memories inherit from an AbstractMemory that encompasses the basic behaviuor of a random access memory, and provides untimed access methods. What was previously called PhysicalMemory is now SimpleMemory, and a subclass of AbstractMemory. All future types of memory controllers should inherit from AbstractMemory. To enable e.g. the atomic CPU and RubyPort to access the now distributed memory, the system has a wrapper class, called PhysicalMemory that is aware of all the memories in the system and their associated address ranges. This class thus acts as an infinitely-fast bus and performs address decoding for these "shortcut" accesses. Each memory can specify that it should not be part of the global address map (used e.g. by the functional memories by some testers). Moreover, each memory can be configured to be reported to the OS configuration table, useful for populating ATAG structures, and any potential ACPI tables. Checkpointing support currently assumes that all memories have the same size and organisation when creating and resuming from the checkpoint. A future patch will enable a more flexible re-organisation. --HG-- rename : src/mem/PhysicalMemory.py => src/mem/AbstractMemory.py rename : src/mem/PhysicalMemory.py => src/mem/SimpleMemory.py rename : src/mem/physical.cc => src/mem/abstract_mem.cc rename : src/mem/physical.hh => src/mem/abstract_mem.hh rename : src/mem/physical.cc => src/mem/simple_mem.cc rename : src/mem/physical.hh => src/mem/simple_mem.hh