205f8fdb5d
The TBEStorage is used to track the resources consumed by the TBETable,
i.e. the number of available TBE slots.
structure(TBEStorage, external ="yes") {
int size();
int capacity();
int reserved();
int slotsAvailable();
bool areNSlotsAvailable(int n);
void incrementReserved();
void decrementReserved();
int addEntryToNewSlot();
void addEntryToSlot(int slot);
void removeEntryFromSlot(int slot);
}
TBEStorage resource tracking has two main differences from TBETable:
1) Allows slot reservation. This is useful to implement protocols that
employ retry/credit messages instead of stall when the controller runs
out of TBEs to accept new request.
2) Can also assign multiple entries to the same slot. This is useful to
more easily model cases where multiple transactions share the same TBE
resource (i.e. the slot).
E.g: a request that triggers a replacement in a system without
dedicated WB/Eviction buffer; both transactions can can have separate
logical TBEs associated to the same slot.
The motivation for having a separate structures for tracking TBEs
availability are twofold:
- Keeps TBETable simple and without the additional overhead for
protocols that do not need these additional features.
- Having two separate transactions sharing the same TBE resource using
the current TBETable would be cumbersome since the TBETable is indexed
by the transaction address.
Change-Id: I64106d50068320bc925243732ef8ff9ef0b6c4bf
Signed-off-by: Tiago Mück <tiago.muck@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/41157
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This is the gem5 simulator. The main website can be found at http://www.gem5.org A good starting point is http://www.gem5.org/about, and for more information about building the simulator and getting started please see http://www.gem5.org/documentation and http://www.gem5.org/documentation/learning_gem5/introduction. To build gem5, you will need the following software: g++ or clang, Python (gem5 links in the Python interpreter), SCons, SWIG, zlib, m4, and lastly protobuf if you want trace capture and playback support. Please see http://www.gem5.org/documentation/general_docs/building for more details concerning the minimum versions of the aforementioned tools. Once you have all dependencies resolved, type 'scons build/<ARCH>/gem5.opt' where ARCH is one of ARM, NULL, MIPS, POWER, SPARC, or X86. This will build an optimized version of the gem5 binary (gem5.opt) for the the specified architecture. See http://www.gem5.org/documentation/general_docs/building for more details and options. The basic source release includes these subdirectories: - configs: example simulation configuration scripts - ext: less-common external packages needed to build gem5 - src: source code of the gem5 simulator - system: source for some optional system software for simulated systems - tests: regression tests - util: useful utility programs and files To run full-system simulations, you will need compiled system firmware (console and PALcode for Alpha), kernel binaries and one or more disk images. If you have questions, please send mail to gem5-users@gem5.org Enjoy using gem5 and please share your modifications and extensions.