Create a function to encapsulate mapping an address in gem5's
address space to the host's address space. The returned value can
be used to access the contents of the given address.
As a side effect, make the local variable hostAddr use snake_case
to comply with gem5's coding style.
Change-Id: I2445d3ab4c7ce5746182b307c26cbafc68aa139c
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22610
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Members `tc` and `ongoingTranslation` were uninitialized in the constructor for
`QueuedPrefetcher::DeferredPacket`. If `ongoingTranslation` is not initialized to
`false` by default, some translation requests from queued prefetchers are not
properly handled and executions are nondeterministic.
Change-Id: Ia278f9e74847d6b847984d47f6a45643bae57794
Signed-off-by: Isaac Sánchez Barrera <isaac.sanchez@bsc.es>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22844
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The type of the local unique_ptr variable was different from the return type.
In C++11 because of such difference, a copy-ellision would not be possible,
and that required the use of a std::move.
In C++14 the restriction of same types being required was removed, so
std::move would not be needed anymore.
With the addition of the -Wredundant-move warning in newer compilers, having
the std::move on the return became an issue, breaking compilation.
Change-Id: I45d18dfc500bb5db5fe360814feb91853c735a19
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22403
Tested-by: kokoro <noreply+kokoro@google.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
This patch was created by Bihn Pham during his internship at AMD.
This patch fixes a very significant performance bug when using the O3
CPU model and Ruby. The issue was Ruby returned false when it received
a request to the same address that already has an outstanding request or
when the memory is blocked. As a result, O3 unnecessary squashed the
pipeline and re-executed instructions. This fix merges readRequestTable
and writeRequestTable in Sequencer into a single request table that
keeps track of all requests and allows multiple outstanding requests to
the same address. This prevents O3 from squashing the pipeline.
Change-Id: If934d57b4736861e342de0ab18be4feec464273d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21219
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Typically, a memory controller is assigned an address range of the
form [start, end). This address range might be interleaved and
therefore only a non-continuous subset of the addresses in the address
range is handed by this controller.
Prior to this patch, the DRAM controller was unaware of the
interleaving and as a result the address range could affect the
mapping of addresses to DRAM ranks, rows and columns. This patch
changes the DRAM controller, to transform the input address to a
continuous range of the form [0, size). As a result the DRAM
controller always operates on a dense and continuous address range
regardlesss of the system configuration.
Change-Id: I7d273a630928421d1854658c9bb0ab34e9360851
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19328
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Wendy Elsasser <wendy.elsasser@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Often a request that hits on an MSHR has to be deferred as it can't be
serviced by the current response.
For example, a request that requires writable has to be deferred when
the response is expected to bring in a read-only copy of the
block. However, there are cases where the response, although not
expected to do so, brings a writable copy and as a result we also
service deferred targets. In such cases, we promote deferred targets
up until the first that can't be serviced by the current response
(e.g., cache maintainance operation). If the first deferred target is
incompatible we don't promote any targets at all.
Change-Id: Ib3e13be51120b7c0f0053b83b76bde03e1b7dd4e
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22127
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
The MSHR keeps track of outstanding writes and services them as a
whole line write whenever possible. To do this the outstanding writes
have to be compatible (e.g., not strictly ordered). Prior to this
change, due to this tracking mechanism, the MSHR would not service a
WriteLineReq with flags that do not allow merging as a full line write
even if it was the first target triggering an assertion. This
changeset fixes this bug.
Change-Id: I2cbf5ece0c108c1fcfe6855e8f194408d5ab8ce2
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/22126
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Tested-by: kokoro <noreply+kokoro@google.com>
Modify second chance replacement policy so that entries are inserted
without a second chance. Previously, the second chance bit was set
to true when a cache line was inserted. So the cache line would gain
its second chance when inserting. This is wrong because the cache
block will only get a second chance when it hits.
Here's a quoted citation for the second chance replacement policy:
"Whenever the algorithm examines a page entry, it extracts the associated
usage bit and enters it into the high-order position of a k-bit shift
register after shifting the contents of the register one bit-position
lower. Then if the shift register is nonzero, the page is retained; if the
shift register is zero, the page is replaced by the new page. In either
case the usage bit for the page is turned off and the circular list
pointer is advanced."
(A Paging Experiment with the Multics System, FJ Corbato, 1968)
Change-Id: I0d07e56aa16c67dd36e0d490c3f457f91e46f320
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20882
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Add support in Ruby to use all replacement policies in Classic.
Furthermore, if new replacement policies are added to the
Classic system, the Ruby system will recognize new policies
without any other changes in Ruby system. The following list
all the major changes:
* Make Ruby cache entries (AbstractCacheEntry) inherit from
Classic cache entries (ReplaceableEntry). By doing this,
replacement policies can use cache entries from Ruby caches.
AccessPermission and print function are moved from
AbstractEntry to AbstractCacheEntry, so AbstractEntry is no
longer needed.
* DirectoryMemory and all SLICC files are changed to use
AbstractCacheEntry as their cache entry interface. So do the
python files in mem/slicc/ast which check the entry
interface.
* "main='false'" argument is added to the protocol files where
the DirectoryEntry is defined. This change helps
differentiate DirectoryEntry from CacheEntry because they are
both the instances of AbstractCacheEntry now.
* Use BaseReplacementPolicy in Ruby caches instead of
AbstractReplacementPolicy so that Ruby caches will recognize
the replacement policies from Classic.
* Add getLastAccess() and useOccupancy() function to Classic
system so that Ruby caches can use them. Move lastTouchTick
to ReplacementData struct because it's needed by
getLastAccess() to return the correct value.
* Add a 2-dimensional array of ReplacementData in Ruby caches
to store information for different replacement policies. Note
that, unlike Classic caches, where policy information is
stored in cache entries, the policy information needs to be
stored in a new 2-dimensional array. This is due to Ruby
caches deleting the cache entry every time the corresponding
cache line get evicted.
Change-Id: Idff6fdd2102a552c103e9d5f31f779aae052943f
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20879
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
When a writeback needs to be allocated the whenReady field of the
block is not set, and therefore its access latency calculation
uses the previously invalidated value (MaxTick), significantly
delaying execution.
This is fixed by assuming that the data write portion of a write
access is done regardless of previous writes, and that only the
tag latency is important for the critical path latency calculation.
Change-Id: I739132a2deab6eb4c46d084f4ee6dd65177873fd
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/20068
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Note that this changes the stat format used by the DRAM
controller. Previously, it would have a structure looking a bit like
this:
- system
- dram: Main DRAM controller
- dram_0: Rank 0
- dram_1: Rank 1
This structure can't be replicated with new-world stats since stats
are confined to the SimObject name space. This means that the new
structure looks like this:
- system
- dram: Main DRAM controller
- rank0: Rank 0
- rank1: Rank 1
Change-Id: I7435cfaf137c94b0c18de619d816362dd0da8125
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21142
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Reviewed-by: Wendy Elsasser <wendy.elsasser@arm.com>
The cacheProbe() function will return the victim entry, and it gets
called for multiple times in trigger function in a single miss. This
will cause a problem when we try to add a new replacement policy to
the Ruby system. Certain policy, like RRIP, will modify the block
information every time the getVictim() function gets called. To
prevent future problems, we need to store the victim entry, so that
we only call it once in one miss.
Change-Id: Ic5ca05f789d9bbfb963b8e993ef707020f243702
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/21099
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Pouya Fotouhi <pfotouhi@ucdavis.edu>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>
