Architected flat scratch is added in MI300 which store the scratch base
address in dedicated registers rather than in SGPRs. These registers are
used by scratch_ instructions. These are flat instruction which
explicitly target the private memory aperture. These instructions have a
different address calculation than global_ instructions.
This change implements architected flat scratch support, fixes the
address calculation of scratch_ instructions, and implements decodings
for some scratch_ instructions. Previous flat_ instructions which happen
to access the private memory aperture have no change in address
calculation. Since scratch_ instructions are identical to flat_
instruction except for address calculation, the decodings simply reuse
existing flat_ instruction definitions.
Change-Id: I1e1d15a2fbcc7a4a678157c35608f4f22b359e21
This is the version for MI300. For the most part, it is the same as
MI200 with the exception of architected flat scratch (not yet
implemented in gem5) and therefore a new version enum is required.
Change-Id: Id18cd7b57c4eebd467c010a3f61e3117beb8d58a
The accumulation offset is needed for some instructions. In order to
access this value we need to place it somewhere instruction definitions
can access. The most logical place is in the wavefront.
This commit simply copies the value from the HSA task to the wavefront
object.
Change-Id: I44ef62ef32d2421953f096c431dd758e882245b4
The RFC is defaulted to a size of 0 which removes it completely. To use
the RFC set the --register-file-cache-size to a non-zero multiple of
two. In addition, rfc_pipe_length may be altrered to increase or
decrease RFC latency benefit.
Change-Id: I6f5bf5b750eb64155fbc8c8343e9feadce5c9f79
The AMDKernelCode struct is very outdated. Most of the fields are no
longer used and have been replaced with new fields that are used.
Therefore in order to support the new fields the code object needs to be
updated. The new structure is based on the table located at
https://llvm.org/docs/AMDGPUUsage.html#code-object-v3-kernel-descriptor
Most notably this adds the new compute_pgm_rsrc3 and kernarg preload
fields which are new features in gfx90a (MI200). The accum_offset in
compute_pgm_rsrc3 and kergarg preload values are necessary to run
application which enable those features and therefore a way to check
their values is needed.
Also noteable is the removal of enable_sgpr_workgroup_id_{X,Y,Z}. These
seem to be unused in all versions of ROCm that gem5 supports and
therefore these fields can be removed. They are replaced with a reserved
field in the new code object.
Change-Id: I5542442e1e5961b05e17affad0adb5186d6d9d1a
This initialization method is used in gfx90a (MI200). Rather than using
three VGPRs for X,Y,Z dimensions of the kernel, pack them into one
register with 10-bits for each dimensions.
Change-Id: I8e5b681c8287779ff9f80451d6028e862322294a
Memory instructions acquire coalescer tokens in the schedule stage.
Currently this is only done for buffer and flat instructions, but not
flat global or flat scratch. This change now acquires tokens for flat
global and flat scratch instructions. This provides back-pressure to the
CUs and helps to avoid deadlocks in Ruby.
The change also handles returning tokens for buffer, flat global, and
flat scratch instructions. This was previously only being done for
normal flat instructions leading to deadlocks in some applications when
the tokens were exhausted.
To simplify the logic, added a needsToken() method to GPUDynInst which
return if the instruction is buffer or any flat segment.
The waitcnts were also incorrect for flat global and flat scratch. We
should always decrement vmem and exp count for stores and only normal
flat instructions should decrement lgkm. Currently vmem/exp are not
decremented for flat global and flat scratch which can lead to deadlock.
This change set fixes this by always decrementing vmem/exp and lgkm only
for normal flat instructions.
Change-Id: I673f4ac6121e4b5a5e8491bc9130c6d825d95fc5
DispatchId should allocate two SGPRs instead of one. Allocating one was
causing all subsequent SGPR index values to be off by one, leading to
bad addresses for things like flat scratch and private segment. This
field is not used very often so it was not impacting most applications.
Change-Id: I17744e2d099fbc0447f400211ba7f8a42675ea06
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/66711
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
There are two initial scalar register fields that are not initialized in
the wavefront when a task is dispatch. This changeset adds the missing
DispatchId and PrivateSegSize fields. These fields are typically used
when an application is compiled with debug support and are typically not
used in the applications in gem5's test suite.
Change-Id: I5b5fa75e4badfd9ba7588e4cd485ebf75fd5d627
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/64191
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Remove the line "For use for simulation and test purposes only" in files
were AMD is the only copyright holder listed in the header. This happens
to be the case for all files where this line exists, removing it
completely from gem5.
Change-Id: I623f266b002f564301b28774f49081099cfc60fd
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/53943
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.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>
This commit removes functions that indexed into the
vectors that held the operands. Instead, for-each loops
are used, iterating through one of 6 vectors
(src, dst, srcScalar, srcVec, dstScalar, dstVec)
that all hold various (potentially overlapping)
combinations of the operands.
Change-Id: Ia3a857c8f6675be86c51ba2f77e3d85bfea9ffdb
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/42212
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.com>
This change removes the GPUDynInstPtr argument from
getRegisterIndex(). The dynamic inst was only needed
to get access to its parent WF's state so it could
determine the number of scalar registers the wave was
allocated. However, we can simply pass the number of
scalar registers directly. This cuts down on shared
pointer usage.
Change-Id: I29ab8d9a3de1f8b82b820ef421fc653284567c65
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/42210
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Matt Sinclair <mattdsinclair@gmail.com>
Maintainer: Matt Sinclair <mattdsinclair@gmail.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>
Barriers were not modeled properly. Firstly, barriers were
allocated to each WG that was launched, which is not
correct, and the CU would provide an infinite number
of barrier slots. There are a limited number of barrier slots
per CU in reality. In addition, the CU will not allocate
barrier slots to WGs with a single WF (nothing to sync if
only one WF).
Beyond modeling problems, there also the issue of deadlock.
The barrier could deadlock because not all WFs are freed
from the barrier once it has been satisfied. Instead, we
relied on the scoreboard stage to release them lazily,
one-by-one.
Under this implementation the scoreboard may not fully release
all WFs participating in a barrier; this happens because the
first WF to be freed from the barrier could reach an s_barrier
instruction again, forever causing the barrier counts across
WFs to be out-of-sync.
This change refactors the barrier logic to:
1) Create a proper barrier slot implementation
2) Enforce (via a parameter) the number of barrier
slots on the CU.
3) Simplify the logic and cleanup the code (i.e., we
no longer iterate through the entire WF list each
time we check if a barrier is satisfied).
4) Fix deadlock issues.
Change-Id: If53955b54931886baaae322640a7b9da7a1595e0
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/29943
Reviewed-by: Anthony Gutierrez <anthony.gutierrez@amd.com>
Maintainer: Anthony Gutierrez <anthony.gutierrez@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Remove the read/write tables and coalescing table and introduce a two
levels of tables for uncoalesced and coalesced packets. Tokens are
granted to GPU instructions to place in uncoalesced table. If tokens
are available, the operation always succeeds such that the 'Aliased'
status is never returned. Coalesced accesses are placed in the
coalesced table while requests are outstanding. Requests to the same
address are added as targets to the table similar to how MSHRs
operate.
Change-Id: I44983610307b638a97472db3576d0a30df2de600
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27429
Reviewed-by: Bradford Beckmann <brad.beckmann@amd.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Bradford Beckmann <brad.beckmann@amd.com>
Tested-by: kokoro <noreply+kokoro@google.com>
The clang compiler complains that the wavefront member in
the GpuISA class is unused. This changeset removes the member,
because it does not appear serve a purpose.
the GPUISA class is meant to encapsulate any ISA-specific behavior - special
register accesses, isa-specific WF/kernel state, etc. - in a generic enough
way so that it may be used in ISA-agnostic code.
gpu-compute: use the GPUISA object to advance the PC
the GPU model treats the PC as a pointer to individual instruction objects -
which are store in a contiguous array - and not a byte address to be fetched
from the real memory system. this is ok for HSAIL because all instructions
are considered by the model to be the same size.
in machine ISA, however, instructions may be 32b or 64b, and branches are
calculated by advancing the PC by the number of words (4 byte chunks) it
needs to advance in the real instruction stream. because of this there is
a mismatch between the PC we use to index into the instruction array, and
the actual byte address PC the ISA expects. here we move the PC advance
calculation to the ISA so that differences in the instrucion sizes may be
accounted for in generic way.
because every taken branch causes fetch to be discarded, we move the call
to the WF to avoid to have to call it from each and every branch instruction
type.
this patch removes the GPUStaticInst enums that were defined in GPU.py.
instead, a simple set of attribute flags that can be set in the base
instruction class are used. this will help unify the attributes of HSAIL
and machine ISA instructions within the model itself.
because the static instrution now carries the attributes, a GPUDynInst
must carry a pointer to a valid GPUStaticInst so a new static kernel launch
instruction is added, which carries the attributes needed to perform a
the kernel launch.
This patch adds a method to the Wavefront class to compute the actual workgroup
size. This can be different from the maximum workgroup size specified when
launching the kernel through the NDRange object. Current solution is still not
optimal, as we are computing these for each wavefront and the dispatcher also
needs to have this information and can't actually call
Wavefront::computeActuallWgSz before the wavefronts are being created. A long
term solution would be to have a Workgroup class that deals with all these
details.
This patch adds methods to serialize the context of a particular wavefront
to the simulated system memory. Context serialization is used when a wavefront
is preempeted (i.e. context switch).
std::stack has no iterators, therefore the reconvergence stack can't be
iterated without poping elements off. We will be using std::list instead to be
able to iterate for saving and restoring purposes.
Eliminate the VSZ constant that defined the Wavefront size (in numbers of work
items); replaced it with a parameter in the GPU.py configuration script.
Changed all data structures dependent on the Wavefront size to be dynamically
sized. Legal values of Wavefront size are 16, 32, 64 for now and checked at
initialization time.
Fixing an issue with regStats not calling the parent class method
for most SimObjects in Gem5. This causes issues if one adds new
stats in the base class (since they are never initialized properly!).
Change-Id: Iebc5aa66f58816ef4295dc8e48a357558d76a77c
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>
Both Memory Fence is now flagged as Global Memory only to avoid resource
oversubscribing.
Flat instructions now check for Shared Memory resource busy to avoid
oversubscribing resources.
All WaitClass resources now use cycles (not ticks) to register the number
of pipe stages between Scoreboard and Execute to be consistent with
instruction scheduling logic which always used clock cycles.
