28 Commits

Author SHA1 Message Date
Johannes Doerfert
3de645efe3 [OpenMP][NFC] Split the reduction buffer size into two components
Before we tracked the size of the teams reduction buffer in order to
allocate it at runtime per kernel launch. This patch splits the number
into two parts, the size of the reduction data (=all reduction
variables) and the (maximal) length of the buffer. This will allow us to
allocate less if we need less, e.g., if we have less teams than the
maximal length. It also allows us to move code from clangs codegen into
the runtime as we now know how large the reduction data is.
2023-11-06 11:50:41 -08:00
Johannes Doerfert
b8cbc5c02c
[OpenMP] Introduce the KernelLaunchEnvironment as implicit argument (#70401)
The KernelEnvironment is for compile time information about a kernel. It
allows the compiler to feed information to the runtime. The
KernelLaunchEnvironment is for dynamic information *per* kernel launch.
It allows the rutime to feed information to the kernel that is not
shared with other invocations of the kernel. The first use case is to
replace the globals that synchronize teams reductions with per-launch
versions. This allows concurrent teams reductions. More uses cases will
follow, e.g., per launch memory pools.

Fixes: https://github.com/llvm/llvm-project/issues/70249
2023-10-31 19:38:43 -07:00
Mehdi Amini
f390a76b7e Revert "Revert "[OpenMP][NFC] Add min/max threads/teams count into the KernelEnvironment (#70257)""
This reverts commit ddbaa11e9f43a38d50d62a9b9b07c3653b6bf8ab.

Reapply the original commit, the broken test was repaired in 5e51363f38d083ab326736c0d4d1b5f9fe0de080 in the meantime.
2023-10-26 17:30:01 -07:00
Mehdi Amini
ddbaa11e9f Revert "[OpenMP][NFC] Add min/max threads/teams count into the KernelEnvironment (#70257)"
This reverts commit c2a1249a8257ed033a98e32e425539c6da6700ec.

The MLIR bots are broken with an omp test failure.
2023-10-26 17:25:20 -07:00
Johannes Doerfert
c2a1249a82
[OpenMP][NFC] Add min/max threads/teams count into the KernelEnvironment (#70257)
The runtime needs to know about the acceptable launch bounds, especially
if the compiler (middle- or backend) assumed those bounds. While this
patch does not yet inform the runtime, it stores the bounds in a place
that can/will be accessed and is associated with the kernel.
2023-10-26 14:46:55 -07:00
Johannes Doerfert
0a0c23b9ce [OpenMPOpt][FIX] Properly track changes to NestedParallelism
If we update the state, or indicate a pessimistic fixpoint, we need to
consider NestedParallelism too.

Fixes part of https://github.com/llvm/llvm-project/issues/66708

That said, the reproducer still needs malloc which we don't support on
AMD GPU. Will be added later.
2023-10-20 19:28:09 -07:00
Shilei Tian
10068cd654 [OpenMP] Introduce kernel environment
This patch introduces per kernel environment. Previously, flags such as execution mode are set through global variables with name like `__kernel_name_exec_mode`. They are accessible on the host by reading the corresponding global variable, but not from the device. Besides, some assumptions, such as no nested parallelism, are not per kernel basis, preventing us applying per kernel optimization in the device runtime.

This is a combination and refinement of patch series D116908, D116909, and D116910.

Depend on D155886.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D142569
2023-07-26 13:35:14 -04:00
Joseph Huber
05b181d851 [OpenMP] Make the nested parallelism global hidden
Summary:
These will probably be removed with the kernel environment, but they
should have hidden visibliity so they can be optimized out.
2023-07-24 08:28:54 -05:00
Shilei Tian
6bd74fd65f Revert commits for kernel environment
This reverts commits for kernel environments as they causes issues in AMD BB.
2023-07-23 23:32:31 -04:00
Shilei Tian
c5c8040390 [OpenMP] Introduce kernel environment
This patch introduces per kernel environment. Previously, flags such as execution mode are set through global variables with name like `__kernel_name_exec_mode`. They are accessible on the host by reading the corresponding global variable, but not from the device. Besides, some assumptions, such as no nested parallelism, are not per kernel basis, preventing us applying per kernel optimization in the device runtime.

This is a combination and refinement of patch series D116908, D116909, and D116910.

Depend on D155886.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D142569
2023-07-23 18:36:01 -04:00
Johannes Doerfert
8f4fadd1b4 [OpenMP] Use "kernel" attribute consistently 2023-06-05 16:33:53 -07:00
Shilei Tian
d4ecd1241c Revert "[OpenMP] Introduce kernel environment"
This reverts commit 35cfadfbe2decd9633560b3046fa6c17523b2fa9.

It makes a couple of buildbots unhappy because of the following test failures:
- `Transforms/OpenMP/add_attributes.ll'`
- `mapping/declare_mapper_target_data.cpp` on AMDGPU
2023-04-22 20:56:35 -04:00
Shilei Tian
35cfadfbe2 [OpenMP] Introduce kernel environment
This patch introduces per kernel environment. Previously, flags such as execution mode are set through global variables with name like `__kernel_name_exec_mode`. They are accessible on the host by reading the corresponding global variable, but not from the device. Besides, some assumptions, such as no nested parallelism, are not per kernel basis, preventing us applying per kernel optimization in the device runtime.

This is a combination and refinement of patch series D116908, D116909, and D116910.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D142569
2023-04-22 20:46:38 -04:00
Shilei Tian
bdf30603f2 [LLVM][OpenMP] Correct the function signature of __kmpc_parallel_level
`__kmpc_parallel_level` used to be a function w/o any argument, but in the new
device runtime, it accepts two. This patch simply corrects it in `OMPKinds.def`.
```
uint16_t __kmpc_parallel_level(IdentTy *Loc, uint32_t);
```

Reviewed By: jhuber6

Differential Revision: https://reviews.llvm.org/D141655
2023-01-20 09:46:45 -05:00
Nikita Popov
aa8e9fac2a [OpenMP] Convert some tests to opaque pointers (NFC) 2023-01-03 15:03:14 +01:00
Johannes Doerfert
90609fb68f [OpenMP][NFCI] Remove effectively dead code in clang and the runtime
Differential Revision: https://reviews.llvm.org/D136903
2022-12-13 18:44:19 -08:00
Johannes Doerfert
f9c29878b0 Revert "[OpenMP][NFCI] Remove effectively dead code in clang and the runtime"
This reverts commit c1c8cbbf5f29257d084a23a2f6c4236c40b7afb9. One of the
tests seems to be flaky/non-deterministic.
2022-12-12 22:08:28 -08:00
Johannes Doerfert
c1c8cbbf5f [OpenMP][NFCI] Remove effectively dead code in clang and the runtime 2022-12-12 20:55:36 -08:00
Johannes Doerfert
e92891f864 [Attributor] Allow not to default initialize AAs for live internal functions
Outside users of the Attributor, e.g., OpenMP-opt, want to seed AAs
themselves. We should not seed all default AAs one an internal function
becomes live. That said, there should be a callback such that they can
do lazy seeding as well.

Differential Revision: https://reviews.llvm.org/D121489
2022-03-11 16:46:03 -06:00
Arthur Eubanks
05392466f0 Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 13:29:23 -07:00
Arthur Eubanks
569346f274 Revert "Reland [IR] Increase max alignment to 4GB"
This reverts commit 8d64314ffea55f2ad94c1b489586daa8ce30f451.
2021-10-06 11:38:11 -07:00
Arthur Eubanks
8d64314ffe Reland [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 11:03:51 -07:00
Arthur Eubanks
72cf8b6044 Revert "[IR] Increase max alignment to 4GB"
This reverts commit df84c1fe78130a86445d57563dea742e1b85156a.

Breaks some bots
2021-10-06 10:21:35 -07:00
Arthur Eubanks
df84c1fe78 [IR] Increase max alignment to 4GB
Currently the max alignment representable is 1GB, see D108661.
Setting the align of an object to 4GB is desirable in some cases to make sure the lower 32 bits are clear which can be used for some optimizations, e.g. https://crbug.com/1016945.

This uses an extra bit in instructions that carry an alignment. We can store 15 bits of "free" information, and with this change some instructions (e.g. AtomicCmpXchgInst) use 14 bits.
We can increase the max alignment representable above 4GB (up to 2^62) since we're only using 33 of the 64 values, but I've just limited it to 4GB for now.

The one place we have to update the bitcode format is for the alloca instruction. It stores its alignment into 5 bits of a 32 bit bitfield. I've added another field which is 8 bits and should be future proof for a while. For backward compatibility, we check if the old field has a value and use that, otherwise use the new field.

Updating clang's max allowed alignment will come in a future patch.

Reviewed By: hans

Differential Revision: https://reviews.llvm.org/D110451
2021-10-06 09:54:14 -07:00
Shilei Tian
423d34f74a [OpenMP][Offloading] Change bool IsSPMD to int8_t Mode in __kmpc_target_init and __kmpc_target_deinit
This is a follow-up of D110029, which uses bitset to indicate execution mode. This patches makes the changes in the function call.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D110279
2021-09-22 17:16:41 -04:00
Roman Lebedev
564d85e090
The maximal representable alignment in LLVM IR is 1GiB, not 512MiB
In LLVM IR, `AlignmentBitfieldElementT` is 5-bit wide
But that means that the maximal alignment exponent is `(1<<5)-2`,
which is `30`, not `29`. And indeed, alignment of `1073741824`
roundtrips IR serialization-deserialization.

While this doesn't seem all that important, this doubles
the maximal supported alignment from 512MiB to 1GiB,
and there's actually one noticeable use-case for that;
On X86, the huge pages can have sizes of 2MiB and 1GiB (!).

So while this doesn't add support for truly huge alignments,
which i think we can easily-ish do if wanted, i think this adds
zero-cost support for a not-trivially-dismissable case.

I don't believe we need any upgrade infrastructure,
and since we don't explicitly record the IR version,
we don't need to bump one either.

As @craig.topper speculates in D108661#2963519,
this might be an artificial limit imposed by the original implementation
of the `getAlignment()` functions.

Differential Revision: https://reviews.llvm.org/D108661
2021-08-26 12:53:39 +03:00
Joseph Huber
640091884f [OpenMP] AlwaysInline __kmpc_parallel_51 to improve inlining hueristics
This patch adds the `AlwaysInline` attribute to the `__kmpc_parallel_51`
device runtime call. This improves inlining heuristics which encourages
the indirect function pointer arguemnt to also be inlined. This greatly
improves performance for a few applications whose outlined regions were
not inlined otherwise.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D107839
2021-08-10 14:41:43 -04:00
Shilei Tian
e97e0a4fad [AbstractAttributor] Fold __kmpc_parallel_level if possible
Similar to D105787, this patch tries to fold `__kmpc_parallel_level` if possible.
Note that `__kmpc_parallel_level` doesn't take activeness into consideration,
based on current `deviceRTLs`, its return value can be such as 0, 1, 2, instead
of 0, 129, 130, etc. that also indicate activeness.

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D106154
2021-07-26 22:46:19 -04:00