The only difference between the TaggedEntry and the newly defined
CacheEntry is the presence of the secure flag in the first case. The
need to tag a cache entry according to the security bit required the
overloading of the matching methods in the TaggedEntry class to take
security into account (See matchTag [1]), and the persistance after
PR #745 of the AssociativeSet class which is basically identical
to its AssociativeCache superclass, only it overrides its virtual
method to match the tag according to the secure bit as well.
The introduction of the KeyType parameter in the previous commit
will smoothe the differences and help unifying the interface.
Rather than overloading and overriding to account for a different
signature, we embody the difference in the KeyType class. A
CacheEntry will match with KeyType = Addr,
whereas a TaggedEntry will use the following lookup type proposed in this
patch:
struct KeyType {
Addr address;
bool secure;
}
This patch is partly reverting the changes in #745 which were
reimplementing TaggedEntry on top of the CacheEntry. Instead
we keep them separate as the plan is to allow different
entry types with templatization rather than polymorphism.
As a final note, I believe a separate commit will have to
change the naming of our entries; the CacheEntry should
probably be renamed into TaggedEntry and the current TaggedEntry
into something that reflect the presence of the security bit
alongside the traditional address tag
[1]: https://github.com/gem5/gem5/blob/stable/\
src/mem/cache/tags/tagged_entry.hh#L81
Change-Id: Ifc104c8d0c1d64509f612d87b80d442e0764f7ca
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
This is a first step towards offloading some of the partitioning
logic to the partitioning manager. We start with this patch
by replacing the static readPacketPartitionId into a virtual
method owned by the manager.
The issue with readPacketPartitionId as of now is that it relies
on the fixed PartitionFieldExtention.
We want user to be able to extract the partitionId more flexibly
and this requires using a SimObject
Change-Id: I3bd2e81e2a97c55fc83548956fc59f422c8049a6
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
hasBeenPrefetched can now take a requestor id and returns true only if
the block was prefetched by a prefetcher with the same id. This may be
necessary to properly train multiple prefetchers attached to the same
cache. If returns true if the block was prefetched by any prefetcher
when the id is not provided.
Related JIRA:
https://gem5.atlassian.net/browse/GEM5-457https://gem5.atlassian.net/browse/GEM5-1112
Change-Id: I205e000fd5ff100e5a5d24d88bca7c6a46689ab2
Signed-off-by: Tiago Mück <tiago.muck@arm.com>
This patches decouples the prefetchers from the cache implementation
as the first step to allow using the classic prefetchers with ruby
caches. The prefetchers that need do cache lookups can do so using
the accessor object provided when the probes are notified. This may
also facilitate connecting the same prefetcher to multiple caches.
Related JIRA:
https://gem5.atlassian.net/browse/GEM5-457https://gem5.atlassian.net/browse/GEM5-1112
Change-Id: I4fee1a3613ae009fabf45d7b747e4582cad315ef
Signed-off-by: Tiago Mück <tiago.muck@arm.com>
Apply the gem5 namespace to the codebase.
Some anonymous namespaces could theoretically be removed,
but since this change's main goal was to keep conflicts
at a minimum, it was decided not to modify much the
general shape of the files.
A few missing comments of the form "// namespace X" that
occurred before the newly added "} // namespace gem5"
have been added for consistency.
std out should not be included in the gem5 namespace, so
they weren't.
ProtoMessage has not been included in the gem5 namespace,
since I'm not familiar with how proto works.
Regarding the SystemC files, although they belong to gem5,
they actually perform integration between gem5 and SystemC;
therefore, it deserved its own separate namespace.
Files that are automatically generated have been included
in the gem5 namespace.
The .isa files currently are limited to a single namespace.
This limitation should be later removed to make it easier
to accomodate a better API.
Regarding the files in util, gem5:: was prepended where
suitable. Notice that this patch was tested as much as
possible given that most of these were already not
previously compiling.
Change-Id: Ia53d404ec79c46edaa98f654e23bc3b0e179fe2d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/46323
Maintainer: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Bobby R. Bruce <bbruce@ucdavis.edu>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
As part of recent decisions regarding namespace
naming conventions, all namespaces will be changed
to snake case.
::Stats became ::statistics.
"statistics" was chosen over "stats" to avoid generating
conflicts with the already existing variables (there are
way too many "stats" in the codebase), which would make
this patch even more disturbing for the users.
Change-Id: If877b12d7dac356f86e3b3d941bf7558a4fd8719
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45421
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
As part of recent decisions regarding namespace
naming conventions, all namespaces will be changed
to snake case.
::Prefetcher became ::prefetcher.
"prefetch" was chosen over "prefetcher" to avoid generating
conflicts with the already existing variables. "prefetcher"
is a name that is expected to be more common in user's code
than "prefetch".
Change-Id: I8f07217f278a0229e05545b7847f2620ed208c66
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45410
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Hoa Nguyen <hoanguyen@ucdavis.edu>
As part of recent decisions regarding namespace
naming conventions, all namespaces will be changed
to snake case.
::Compressor became ::compression.
"compression" was chosen over "compressor" to avoid
generating conflicts with the already existing variables,
as well as because the namespace contains more than solely
compressors (e.g., encoders).
Change-Id: I7054845984784b0dffcc4fb90d66c5096a64194d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/45406
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The systemc dir was not included in this fix.
First it was identified that there were only occurrences
at 0, 1, and 2 levels of indentation (and 2 of 2 spaces,
1 of 3 spaces and 2 of 12 spaces), using:
grep -nrE --exclude-dir=systemc \
"^ *enum [A-Za-z].* {$" src/
Then the following commands were run to replace:
<indent level>enum X ... {
by:
<indent level>enum X ...
<indent level>{
Level 0:
grep -nrl --exclude-dir=systemc \
"^enum [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^enum ([A-Za-z].*) \{$/enum \1\n\{/g'
Level 1:
grep -nrl --exclude-dir=systemc \
"^ enum [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^ enum ([A-Za-z].*) \{$/ enum \1\n \{/g'
and so on.
Change-Id: Ib186cf379049098ceaec20dfe4d1edcedd5f940d
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/43326
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Gabe Black <gabe.black@gmail.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The systemc dir was not included in this fix.
First it was identified that there were only occurrences
at 0, 1, and 2 levels of indentation, using:
grep -nrE --exclude-dir=systemc \
"^ *class [A-Za-z].* {$" src/
Then the following commands were run to replace:
<indent level>class X ... {
by:
<indent level>class X ...
<indent level>{
Level 0:
grep -nrl --exclude-dir=systemc
"^class [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^class ([A-Za-z].*) \{$/class \1\n\{/g'
Level 1:
grep -nrl --exclude-dir=systemc \
"^ class [A-Za-z].* {$" src/ | \
xargs sed -Ei \
's/^ class ([A-Za-z].*) \{$/ class \1\n \{/g'
and so on.
Change-Id: I17615ce16a333d69867b27c7bae0f4fdafd8b2eb
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/39015
Reviewed-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Maintainer: Giacomo Travaglini <giacomo.travaglini@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Data contractions happen when a block passes from a less compressed
(e.g., uncompressed) to a more compressed (e.g., compressed) state.
Some compaction methods enforce that a block can only be allocated
in a location matches an exact compression factor, thus on data
contractions such blocks must be moved to another location, or
they must be padded to fake a bigger size.
For compaction methods that do not have that limitation, performance
can be improved if the contracted block is moved to co-allocate with
another existing entry, since it frees up an entry.
Change-Id: I302bc561b897f9d3ce1426331fe4b5c2df76f4b5
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36578
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
When searching for victims of a data expansion a simple approach to
make room for the expanded block is to evict every co-allocatable
block. This, however, ignores replacement policies and tends to be
inefficient. Besides, some cache compaction policies do not allow
blocks that changed their compression ratio to be allocated in the
same location (e.g., Skewed Compressed Caches), so they must be
moved elsewhere.
The replacement policy approach asks the replacement policy which
block(s) would be the best to evict in order to make room for the
expanded block. The other approach, on the other hand, simply evicts
all co-allocated entries. In the case the replacement policy selects
the superblock of the block being expanded, we must make sure the
latter is not evicted/moved by mistake.
This patch also allows the user to select which approach they would
like to use.
Change-Id: Iae57cf26dac7218c51ff0169a5cfcf3d6f8ea28a
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36577
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The create() method on Params structs usually instantiate SimObjects
using a constructor which takes the Params struct as a parameter
somehow. There has been a lot of needless variation in how that was
done, making it annoying to pass Params down to base classes. Some of
the different forms were:
const Params &
Params &
Params *
const Params *
Params const*
This change goes through and fixes up every constructor and every
create() method to use the const Params & form. We use a reference
because the Params struct should never be null. We use const because
neither the create method nor the consuming object should modify the
record of the parameters as they came in from the config. That would
make consuming them not idempotent, and make it impossible to tell what
the actual simulation configuration was since it would change from any
user visible form (config script, config.ini, dot pdf output).
Change-Id: I77453cba52fdcfd5f4eec92dfb0bddb5a9945f31
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/35938
Reviewed-by: Gabe Black <gabeblack@google.com>
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Gabe Black <gabeblack@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Creation of the Compressor namespace. It encapsulates all the cache
compressors, and other classes used by them.
The following classes have been renamed:
BaseCacheCompressor -> Base
PerfectCompressor - Perfect
RepeatedQwordsCompressor -> RepeatedQwords
ZeroCompressor -> Zero
BaseDictionaryCompressor and DictionaryCompressor were not renamed
because the there is a high probability that users may want to
create a Dictionary class that encompasses the dictionary contained
by these compressors.
To apply this patch one must force recompilation (e.g., by deleting
it) of build/<arch>/params/BaseCache.hh (and any other files that
were previously using these compressors).
Change-Id: I78cb3b6fb8e3e50a52a04268e0e08dd664d81230
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/33294
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
This reverts commit bf0a722acd.
Reason for revert: This patch introduces a bug:
The problem here is that the insertion of block A may cause the
eviction of block B, which on the lower level may cause the
eviction of block A. Since A is not marked as present yet, A is
"safely" removed from the snoop filter
However, by reverting it, using atomic and a Tags sub-class that
can generate multiple evictions at once becomes broken when using
Atomic mode and shall be fixed in a future patch.
Change-Id: I5b27e54b54ae5b50255588835c1a2ebf3015f002
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/19088
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Previously all atomic writebacks concerned a single block,
therefore, when a block was evicted, no other block would be
pending eviction. With sector tags (and compression),
however, a single replacement can generate many evictions.
This can cause problems, since a writeback that evicts a block
may evict blocks in the lower cache. If one of these conflict
with one of the blocks pending eviction in the higher level, the
snoop must inform it to the lower level. Since atomic mode does
not have a writebuffer, this kind of conflict wouldn't be noticed.
Therefore, instead of evicting multiple blocks at once, we
do it one by one.
Change-Id: I2fc2f9eb0f26248ddf91adbe987d158f5a2e592b
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18209
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
When a block in compressed form is overwriten, it may change
its size. If the new compressed size is bigger, and the total
size becomes bigger than the block size, one or more blocks
will have to be evicted. This is called data expansion, or
fat writes.
This change assumes that a first level cache cannot have a
compressor, since otherwise data expansion should have been
handled for atomic operations and writes. As such, data
expansions should only be seen on writebacks. As writebacks
are forwarded to the next level when failed, there should
be no data expansions when servicing misses either.
This patch adds the functionality to handle data expansions
by evicting the co-allocated blocks to make room for an
expanded block.
Change-Id: I0bd77bf6446bfae336889940b2f75d6f0c87e533
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/12087
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Tested-by: kokoro <noreply+kokoro@google.com>
MemObject doesn't provide anything beyond its base ClockedObject any
more, so this change removes it from most inheritance hierarchies.
Occasionally MemObject is replaced with SimObject when I was fairly
confident that the extra functionality of ClockedObject wasn't needed.
Change-Id: Ic014ab61e56402e62548e8c831eb16e26523fdce
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/18289
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Gabe Black <gabeblack@google.com>
Some accesses only need to search for a tag in the tag array, with
no need to touch the data array. This is the case for CleanEvicts,
evicts that don't find a corresponding block entry (since a write
cannot be done in parallel with tag lookup), and maintenance
operations.
Change-Id: I7365a915500b5d7ab636d49a9acc627072a7f58e
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/14878
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Previously the bus delay was being ignored for the access latency
calculation, and then applied on top of the access latency. This
patch fixes the order, as first the packet must arrive before the
access starts.
Change-Id: I6d55299a911d54625c147814dd423bfc63ef1b65
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/14876
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
This implementation is based in the description available in:
Jinchun Kim, Seth H. Pugsley, Paul V. Gratz, A. L. Narasimha Reddy,
Chris Wilkerson, and Zeshan Chishti. 2016.
Path confidence based lookahead prefetching.
In The 49th Annual IEEE/ACM International Symposium on Microarchitecture
(MICRO-49). IEEE Press, Piscataway, NJ, USA, Article 60, 12 pages.
Change-Id: I4b8b54efef48ced7044bd535de9a69bca68d47d9
Reviewed-on: https://gem5-review.googlesource.com/c/14819
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Access latency was not being calculated properly, as it was
always assuming that for hits reads take as long as writes,
and that parallel accesses would produce the same latency
for read and write misses.
By moving the calculation to the Cache we can use the write/
read information, reduce latency variables duplication and
remove Cache dependency from Tags.
The tag lookup latency is still calculated by the Tags.
Change-Id: I71bc68fb5c3515b372c3bf002d61b6f048a45540
Signed-off-by: Daniel R. Carvalho <odanrc@yahoo.com.br>
Reviewed-on: https://gem5-review.googlesource.com/c/13697
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
Enable the cache to detect contiguous writes and hold on to the MSHR
long enough to allow the entire line to be written. If the whole line
is written, the MSHR will be sent out as an invalidation requests, as
it is part of a whole-line write, i.e. no-fetch-on-write.
The cache is also able to switch to a write-no-allocate policy on the
actual completion of the writes, and instead use the tempBlock and
turn the write operation into a writeback.
These policies are all well-known, and described in works such as
Jouppi, Cache Write Policies and Performance, vol 21, no 2, ACM, 1993.
Change-Id: I19792f2970b3c6798c9b2b493acdd156897284ae
Reviewed-on: https://gem5-review.googlesource.com/c/12907
Reviewed-by: Daniel Carvalho <odanrc@yahoo.com.br>
Maintainer: Nikos Nikoleris <nikos.nikoleris@arm.com>
