# Feature
Inductor sometimes uses `Identity` functions to group various terms of an expression. While this is convenient in some scenarios, it can frustrate pattern matching. For example, when we're matching an indexing expression to tell if it can be represented as a block pointer, that analysis should be invariant to `Identity`'s.
This PR adds a few features to achieve this invariance.
- Create a new expansion mode `expr.expand(identity=True)`, which removes all `Identity` functions from the expression.
- Preprocess the expression with this expansion prior to pattern matching.
- Bonus: create a new test utility function called `dummy_graph()`, which creates a simple `GraphLowering`. This is useful for testing the pattern matcher, as we need to initialize `V.graph` before we can access `V.graph.sizevars`.
# Test plan
This PR adds a few new unit tests:
- Added a unit test specifically for `expr.expand(identity=True)`.
- Added a new unit test module for the block pattern matcher. Tested that we can correctly match some example patterns containing Identity ops.
I originally intended to add an end to end test compiling pointwise cat, and mapping the corresponding memory accesses to block pointers. However, it looks like that will take more work, since the [relevant code path](https://github.com/pytorch/pytorch/blob/main/torch/_inductor/codegen/triton.py#L1306) disables block pointer analysis. It might be better to defer that to a future PR.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/146000
Approved by: https://github.com/eellison, https://github.com/jansel
* Let's say x is an integer beyond 2^53 where Python floats lose precision i.e. can't increment by 1.
* Therefore, float(x) will lose precision and won't retain the exact value of x even though it's an integer.
* That means `FloorToInt(very_large_number)` will lose precision if we cast it to float
```
>>> int(float(1000000007999999992))
1000000008000000000
```
This means when we try to do this in set_replacement():
32bb6f83d5/torch/fx/experimental/symbolic_shapes.py (L6011-L6019)
We run into this:
```
TORCH_LOGS="+torch.fx.experimental.symbolic_shapes" pytest -s test_export.py -k test_replace_unbacked_with_very_large_upperbound
File "/data/users/colinpeppler/pytorch/torch/fx/experimental/symbolic_shapes.py", line 6258, in _maybe_guard_rel
self._set_replacement(rhs, self._find(lhs), "trivial_rhs")
File "/data/users/colinpeppler/pytorch/torch/fx/experimental/symbolic_shapes.py", line 6039, in _set_replacement
assert tgt_bound.issubset(
torch._dynamo.exc.TorchRuntimeError: Failed running call_function <built-in function add>(*(FakeTensor(..., size=(2*s0,)), FakeTensor(..., size=(u0,))), **{}):
tgt_bound=VR[4, 1000000008000000000] not a subset of src_bound=VR[4, 1000000007999999992]
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/146001
Approved by: https://github.com/bobrenjc93
ghstack dependencies: #145898
I encountered this C++ compilation error.
```
579 | int64_t var_6 = (static_cast<int64_t>(std::floor((1.0/2.0)*u0)) | static_cast<int64_t>(std::floor((1.0/4.0)*static_cast<int64_t>(std::floor((1.0/2.0)*u0))))) | std::floor((1.0/16.0)*(static_cast<int64_t>(std::floor((1.0/2.0)*u0)) | static_cast<int64_t>(std::floor((1.0/4.0)*static_cast<int64_t>(std::floor((1.0/2.0)*u0))))));
| ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
| | |
| int64_t {aka long int} double
```
Then, I figured out where this std::floor came from with the help of Bob's guard provenance tool. It comes from RShift which is used in `triton.next_power_of_2`.
---
Before, we used `std::floor`
```
int64_t var_6 = (
static_cast<int64_t>(std::floor((1.0/2.0)*u0)) |
static_cast<int64_t>(std::floor((1.0/4.0)*static_cast<int64_t>(std::floor((1.0/2.0)*u0)))))
| std::floor((1.0/16.0)*(static_cast<int64_t>(std::floor((1.0/2.0)*u0)) # no cast to int here.
| static_cast<int64_t>(std::floor((1.0/4.0)*static_cast<int64_t>(std::floor((1.0/2.0)*u0))))));
```
Now, we use `c10::div_floor_integer` instead
```
int64_t var_6 = (
(c10::div_floor_integer(static_cast<int64_t>(u0), static_cast<int64_t>(2L))) |
(c10::div_floor_integer(static_cast<int64_t>(u0), static_cast<int64_t>(8L)))) |
(c10::div_floor_integer(static_cast<int64_t>((c10::div_floor_integer(static_cast<int64_t>(u0), static_cast<int64_t>(2L)))
| (c10::div_floor_integer(static_cast<int64_t>(u0), static_cast<int64_t>(8L)))), static_cast<int64_t>(16L)));
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/145898
Approved by: https://github.com/desertfire, https://github.com/bobrenjc93
ghstack dependencies: #145802
The codebase has a few locations where callable parameter type information is lost when the unpackings *args and **kwargs are typed as Any. Refactor these instances to retain type information using typing_extensions.ParamSpec.
Also, in these functions, enforce return type with TypeVar.
Addresses #142306
Pull Request resolved: https://github.com/pytorch/pytorch/pull/143797
Approved by: https://github.com/Skylion007
Co-authored-by: Aaron Gokaslan <aaronGokaslan@gmail.com>
Co-authored-by: Xuehai Pan <XuehaiPan@outlook.com>
Preparatory refactor for https://github.com/pytorch/pytorch/pull/137243.
# Feature
This PR changes the `RINDEX` / `"r"` symbol type to `(R0_INDEX, R1_INDEX)` and `("r0_", "r1_")`, respectively. This allows the relevant code to support 2D (often ND) reductions. Unlike the parent PR, this one does not change the tiling algorithm, so `"r1_"` is never used. However, it prepares other parts of the system to handle `"r1_"` once we start using it. This should significantly reduce the chances of hitting merge conflicts, making the parent PR much easier to land.
The only change to the generated triton code is to rename `"rindex"` -> `"r0_index"`, `"RBLOCK"` -> `"R0_BLOCK"`, etc. To maintain compatibilty with existing codegen, this also generates aliases to the old reduction variables like `rindex = r0_index`. If we generated 2D reductions (which this PR will not do), the aliases would be more complicated and would collapse 2D multi-indices to linear indices. See some example kernels in the parent PR.
These aliases can be eliminated by the Triton compiler, and should not impact the final machine code running on the GPU. See the perf testing in the parent PR which confirms the aliases do not impact perf.
# Test plan
The existing CI provides good coverage. This PR modifies the expected code in a few places, renaming reduction variables from `r.*` to `r0_.*`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/142020
Approved by: https://github.com/jansel
Co-authored-by: Jason Ansel <jansel@meta.com>
Summary:
**wins**
on torchrec benchmark, for 2K nodes it save 40seconds
with the recent sympy changes (https://www.internalfb.com/diff/D65883538) we save around 13 second ( with the max opt on).
```
buck2 run fbcode//mode/opt fbcode//torchrec/distributed/tests:pt2_compile_benchmark -- --num-features=200
```
This diff optimizes construction expressions of the form
a+b+c... (all unique symbols).
which are very common in torchrec models.
**How**
Expressions of the form a+b+c are not optimized by add, the only needed optimization is sorting them.
If we have a+b+c and we are adding (d) to it, we can do a binary search to know
the position of (d) and avoid optimizing the new expression by passing the new order.
**Extensions**:
1. support constant terms.
2. support 10a+10b+.. (this will give even more wins will extend the support in second PR)
Differential Revision: D66008482
Pull Request resolved: https://github.com/pytorch/pytorch/pull/140822
Approved by: https://github.com/ezyang
Tested internally here: https://www.internalfb.com/diff/D64057744
This is a reland after previous internal failures.
main change is
```
if min is None and max is None:
torch._check_is_size(size)
return
```
Partially addresses https://github.com/pytorch/pytorch/issues/128150
When you have big sums of values, we end up computing long chains of
binary addition in our FX graph representation. Not only is this ugly,
it also is quadratic, as the sympy.Add constructor is O(N) in number
of arguments. Instead, ensure that we maintain the summation as a
single FX node so we can do the entire addition all in one go.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138660
Approved by: https://github.com/ezyang, https://github.com/bobrenjc93
Fixes: https://github.com/pytorch/pytorch/issues/138069
I tested this by running `python test/inductor/test_torchinductor_dynamic_shapes.py DynamicShapesCpuTests.test_builtins_round_float_ndigits_pos_dynamic_shapes_cpu` before and after the change and verifying no more log spew.
I'm uncertain on if it makes sense to add a test for this PR. Question for reviewers: is there a standard paradigm for testing these log spew based fixed? Happy to add a test if someone can point me towards the right direction.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/138356
Approved by: https://github.com/ezyang
Instead, callback to a missing handler when needed. This greatly speeds things up with the value ranges dict is large. The missing handler is needed because nested ints don't have VRs, but symbolic sizes involving them occasionally show up in compute.
```
TORCHDYNAMO_EXTENDED_DEBUG_CREATE_SYMBOL="s11" TORCH_LOGS=dynamic PYTORCH_TEST_WITH_DYNAMO=1 python test/test_nestedtensor.py TestNestedTensorAutogradCPU.test_dropout_backward_jagged_cpu
```
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136667
Approved by: https://github.com/isuruf
ghstack dependencies: #136429
Partially addresses https://github.com/pytorch/pytorch/issues/128150
When you have big sums of values, we end up computing long chains of
binary addition in our FX graph representation. Not only is this ugly,
it also is quadratic, as the sympy.Add constructor is O(N) in number
of arguments. Instead, ensure that we maintain the summation as a
single FX node so we can do the entire addition all in one go.
update_hint_regression benchmark, before and after:
```
update_hint_regression,compile_time_instruction_count,2648328980
update_hint_regression,compile_time_instruction_count,2563748678
```
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/136429
Approved by: https://github.com/isuruf
