When restoring from a checkpoint, the simulation used to use file handles from
the checkpoint. This disallows multiple separate restore simulations from using
separate input and output files and directories, and plays havoc when the
checkpointed file locations may have changed. Add handling to allow the command
line specified files to be used as input/output for the restored simulation
(Note: this is the similar functionality to FS mode for output and error).
The Minor and o3 cpu models share the branch prediction
code. Minor relies on the BPredUnit::squash() function
to update the branch predictor tables on a branch mispre-
diction. This is fine because Minor executes in-order, so
the update is on the correct path. However, this causes the
branch predictor to be updated on out-of-order branch
mispredictions when using the o3 model, which should not
be the case.
This patch guards against speculative update of the branch
prediction tables. On a branch misprediction, BPredUnit::squash()
calls BpredUnit::update(..., squashed = true). The underlying
branch predictor tests against the value of squashed. If it is
true, it restores any speculatively updated internal state
it might have (e.g., global/local branch history), then returns.
If false, it updates its prediction tables. Previously, exist-
ing predictors did not test against the "squashed" parameter.
To accomodate for this change, the Minor model must now call
BPredUnit::squash() then BPredUnit::update(..., squashed = false)
on branch mispredictions. Before, calling BpredUnit::squash()
performed the prediction tables update.
The effect is a slight MPKI improvement when using the o3
model. A further patch should perform the same modifications
for the indirect target predictor and BTB (less critical).
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
The tournament predictor is presented as doing speculative
update of the global history and non-speculative update
of the local history used to generate the branch prediction.
However, the code does speculative update of both histories.
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
The target of taken conditional direct branches does not
need to be resolved in IEW: the target can be computed at
decode, usually using the decoded instruction word and the PC.
The higher-than-necessary penalty is taken only on conditional
branches that are predicted taken but miss in the BTB. Thus,
this is mostly inconsequential on IPC if the BTB is big/associative
enough (fewer capacity/conflict misses). Nonetheless, what gem5
simulates is not representative of how conditional branch targets
can be handled.
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
cachePorts currently constrains the number of store packets written to the
D-Cache each cycle), but loads currently affect this variable. This leads
to unexpected congestion (e.g., setting cachePorts to a realistic 1 will
in fact allow a store to WB only if no loads have accessed the D-Cache
this cycle). In the absence of arbitration, this patch decouples how many
loads can be done per cycle from how many stores can be done per cycle.
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>
When Ruby controllers stall messages in MessageBuffers, the buffer moves those
messages off the priority heap and into a per-address stall map. When buffers
are finite-sized, the test areNSlotsAvailable() only checks the size of the
priority heap, but ignores the stall map, so the map is allowed to grow
unbounded if the controller stalls numerous messages. This patch fixes the
problem by tracking the stall map size and testing the total number of messages
in the buffer appropriately.
the iterator declared in DMASequencer::ackCallback() is only used in an
assert, this causes clang to fail when building fast. here we move
the find call on the request table directly into the assert.
The aforementioned upgrader in [1] assumes every option in [system]
has a delimiting '.', and also seems to do its rewriting work a bit too
unconditionally. Most checkpoints in the wild don't have this device,
in which case this script should be a safe no-op.
[1] 2aa4d7b dist, dev: Fixed the packet ordering in etherswitch
Change-Id: Icfd0350985109df1628eb9ab864cda42c54060a8
Reviewed-by: Gabor Dozsa <gabor.dozsa@arm.com>
Compute the proper values of the aforementioned registers from
the system configuration rather than configuring the values themselves.
Change-Id: If9774b6610a29568b80ae4866107b9a6a5b5be0f
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Compute the proper values of the aforementioned registers from
the system configuration rather than configuring the values themselves.
Change-Id: Ie7685b5d8b5f2dd9d6380b4af74f16d596b2bfd1
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
The Python wrappers generally assume that destructors are public. Make
the BaseXBar destructor public to avoid confusing the Python wrapper.
Change-Id: If958802409c0be74e875dd6e279742abfdb3ede1
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-by: Curtis Dunham <curtis.dunham@arm.com>
Some configuration scripts need periodic stat dumps. One of the ways
this can be achieved is by using the pariodicStatDump helper
function. This function was previously only exported in the internal
name space. Export it as a normal function in m5.stat instead.
Change-Id: Ic88bf1fd33042a62ab436d5944d8ed778264ac98
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Sascha Bischoff <sascha.bischoff@arm.com>
Builds for the NULL ISA include Device.py, which contains the Python
declaration of DmaDevice, but don't include the actual C++
implementation. Add dma_device.cc to the NULL build to the Python and
C++ worlds consistent again.
Change-Id: I47a57181a1f4d5a7276467678bf16fbc7f161681
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Sascha Bischoff <sascha.bischoff@arm.com>
The header declared in the DmaDevice wrapper doesn't actually contain
the DmaDevice class. This can potentially lead to incorrect type cases
in Swig.
Change-Id: If2266d4180d1d6fd13359a81067068854c5e96fe
Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Sascha Bischoff <sascha.bischoff@arm.com>
This patch detects garnet network deadlock by monitoring
network interfaces. If a network interface continuously
fails to allocate virtual channels for a message, a
possible deadlock is detected.
Two problems may arise when a distributed gem5 simulation terminates:
(i) simulation thread(s) may get stuck in an incomplete synchronisation
event which prohibits processing the simulation exit event; and (ii) a
stale receiver thread may try to access objects that have already been
deleted while exiting gem5. This patch terminates receive threads properly
and aborts the processing of any incomplete synchronisation event.
Change-Id: I72337aa12c7926cece00309640d478b61e55a429
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
This patch adds an IOCache to the example bigLITTLE
configuration. An IOCache is required for correct DMA
transfers when we have caches in the system.
Change-Id: Ifeddc1b360aacbb16b1393f361dd98873c834012
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
This change adds the option to use the memcheck with random memory
hierarchies at the moment limited to a maximum depth of 3 allowing
testing with uncommon topologies.
Change-Id: Id2c2fe82a8175d9a67eb4cd7f3d2e2720a809b60
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Previously when an InvalidateReq snooped a cache with a dirty block or
a pending modified MSHR, it would invalidate the block or set the
postInv flag. The cache would not send an InvalidateResp. though,
causing memory order violations. This patches changes this behavior,
making the cache with the dirty block or pending modified MSHR the
ordering point.
Change-Id: Ib4c31012f4f6693ffb137cd77258b160fbc239ca
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Previously an MSHR with one or more invalidating targets would first
service all targets in the MSHR TargetList and then invalidate the
block. As a result any service snooping targets would lookup in the
cache and incorrectly find the block. This patch forces the
invalidation to happen when the first invalidating target is
encountered.
Change-Id: I9df15de24e1d351cd96f5a2c424d9a03d81c2cce
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
This patch changes an assertion that previously assumed that a non
invalidating snoop request should never be serviced by an
InvalidateReq MSHR. The MSHR serves as the ordering point for the
snooping packet. When the InvalidateResp reaches the cache the
snooping packet snoops the caches above to find the requested
block. One or more of the caches above will have the block since
earlier it has seen a WriteLineReq.
Change-Id: I0c147c8b5d5019e18bd34adf9af0fccfe431ae07
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
When the snoopFilter receives a response, it updates its state using
the hasSharers flag (indicates whether there are more than one copies
of the block in the caches above). The hasSharers flag of the packet
was previously populated when the request was traversing and snooping
the caches looking for the block.
1) When the response is coming from the memory-side port, its order
with respect to other responses is not necessarily preserved (e.g., a
request that arrived second to the xbar can get its response first). As
a result the snoopFilter might process responses out of order updating
its residency information using the non valid hasSharers flag which was
populated much earlier.
2) When the response is from an on-chip, the MSHRs preserve a well
defined order and the hasSharers flag should contain valid
information.
This patch changes the snoopFilter by avoiding the hasSharers flag
when the response is from the memory-side port.
Change-Id: Ib2d22a5b7bf3eccac64445127d2ea20ee74bb25b
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
Previously, a WriteLineReq that missed in a cache would send out an
InvalidateReq if the block lookup failed or an UpgradeReq if the
block lookup succeeded but the block had sharers. This changes ensures
that a WriteLineReq always sends an InvalidateReq to invalidate all
copies of the block and satisfy the WriteLineReq.
Change-Id: I207ff5b267663abf02bc0b08aeadde69ad81be61
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Change-Id: Ie3beeef25331f84a0a5bcc17f7a791f4a829695b
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
This patch fixes an issue where an MSHR would incorrectly be perceived
to provide data to targets arriving after an InvalidateReq. To address
this the InvalidateReq is now treated as isForward, much like an
UpgradeReq that did not hit in the cache.
Change-Id: Ia878444d949539b5c33fd19f3e12b0b8a872275e
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
Previously DPRINTFs printing information about a packet would use ad hoc
formats. This patch changes all DPRINTFs to use the print function
defined by the packet class, making the packet printing format more
uniform and easier to change.
Change-Id: Idd436a9758d4bf70c86a574d524648b2a2580970
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
Previously all traffic generators would use the same value for write
requests. With this change traffic generators use their master id as
the payload of write requests making them more useful for the
memchecker.
Change-Id: Id1a6b8f02853789b108ef6003f4c32ab929bb123
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
A response to a ReadReq can either be a ReadResp or a
ReadRespWithInvalidate. As we add targets to an MSHR for a ReadReq we
assume that the response will be a ReadResp. When the response is
invalidating (ReadRespWithInvalidate) servicing more than one targets
can potentially violate the memory ordering. This change fixes the way
we handle a ReadRespWithInvalidate. When a cache receives a
ReadRespWithInvalidate we service only the first FromCPU target and
all the FromSnoop targets from the MSHR target list. The rest of the
FromCPU targets are deferred and serviced by a new request.
Change-Id: I75c30c268851987ee5f8644acb46f440b4eeeec2
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
Previously the information of whether a response was allocating or not
was a property of the MSHR. This change makes this flag a property of
the TargetList. Differernt TargetLists, e.g. the targets and the
deferred targets lists might have different values. Additionally, the
information about whether each of the target expects an allocating
response is stored inside the TargetList container. This allows for
repopulating the flag in case some of the targets are removed.
Change-Id: If3ec2516992f42a6d9da907009ffe3ab8d0d2021
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
This patch adds support for repopulating the flags of an MSHR
TargetList. The added functionality makes it possible to remove
targets from a TargetList without leaving it in an inconsistent state.
Change-Id: I3f7a8e97bfd3e2e49bebad056d11bbfb087aad91
Reviewed-by: Andreas Hansson <andreas.hansson@arm.com>
Reviewed-by: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
