Tracing through `__init__` is important because it initializes (calls STORE_ATTR) on members. By doing that, we kick in the mutation tracking for these objects. So, things like mutating `_modules` etc is tracked automatically.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/126578
Approved by: https://github.com/jansel
ghstack dependencies: #128001
To fix data-dependent errors we want to recommend that people use `torch._check*` APIs. The `constrain_as*` APIs should be fully subsumed by them, and in the future we should kill them entirely.
Differential Revision: D56774333
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125253
Approved by: https://github.com/ezyang
While studying some tlparse, I noticed that CompilationMetrics was reporting that there was no error for frames that have no nodes. I'm pretty sure we don't actually install a frame in this situation. has_guarded_code will tell us if that's the case, because it says if the GuardedCode object is None or not.
Actually, while working on this, I was wondering if we can ever trigger the "skip this frame entirely, do not trace it ever again" codepath, as best as I could tell, it's impossible for this to happen by the time we get to compilation metrics block.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/125279
Approved by: https://github.com/yanboliang
The important comment:
```
# Whenever we allocate a fresh unbacked Symbol, we add it to this
# pending list. Unbacked symbol allocation can occur at unpredictable
# points during meta tensor propagation, but at some point, the we
# have to know what the binding site for an unbacked symbol is, and
# this is computed when we actually place the node in the graph. The
# important thing is that we always actually handle every unaccounted
# for unbacked symbol, so this list helps us keep track of them and
# then make sure they are all accounted for.
#
# We could potentially give rise to errors earlier by lexically
# scoping when we do propagation, and only allowing unbacked symbols
# to be allocated at this point in time. However this is inconvenient
# to do in Dynamo, because fake tensor propagation is far from when we
# analyze binding sites (set_example_value), so we do it in a more
# mutatey way.
#
# NB: fresh unbacked symbols NEVER get substitutions applied to them,
# they are binding sites!
```
The compute_unbacked_bindings is the other half of the equation: the thing that actually consumes the pending_fresh_unbacked_symbols and does something with them. Important comment:
```
After having run fake tensor propagation and producing example_value
result, traverse example_value looking for freshly bound unbacked
symbols and record their paths for later. It is an error if
we have allocated an unbacked SymInt but it cannot be found in
example_value. (NB: this means if you have a multi-output
function, you must call this on the tuple of tensor output, you
cannot wait!)
```
For example, if I return a tensor with size `[u0, u1]`, and u1 is a fresh unbacked SymInt, then I'll have `{u1: KeyPath(".size(1)")}`, telling me I can get u1 by running `size(1)` on the result of this node. u0 is not fresh (it probably flowed in as an argument), so I don't generate a binding for it.
I eventually intend to propagate this information all the way to Inductor lowering, where extra metadata about unbacked symbol binding will be canonically used for codegen, instead of trying to infer it from defs/uses.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/124290
Approved by: https://github.com/lezcano
I'm going to setup some extra behavior when we set example value, so
I need a convenient place to interpose. I cannot easily do it on
meta itself because its a generic dict with no interposition point.
Signed-off-by: Edward Z. Yang <ezyang@meta.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/124176
Approved by: https://github.com/oulgen
ghstack dependencies: #124105, #124059
Automatic fixes that replaces certain list comprehensions with generator ones where appropriate so that they are immediately consumed. This is preview functionality in ruff for rule C419 and it was automatically applied.
Co-authored-by: Nikita Shulga <2453524+malfet@users.noreply.github.com>
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123960
Approved by: https://github.com/malfet
### Context
In today's Dynamo, we lift all tensors encountered during tracing to be individual graph inputs, even when they were in a container.
And [Dynamo generates](fdc281f258/torch/_dynamo/codegen.py (L371)) the runtime function's signature using the graph's graphargs.
This means that the generated function will have each grapharg as an argument, which is problematic if we want to free the inputs in inductor codegen. See [python function arguments are kept alive for the duration of the function call](https://github.com/pytorch/pytorch/pull/83137#issuecomment-1211320670).
```python
# original code
def forward(inputs):
a, b, c, d, e = inputs
inputs.clear()
out = a
out += b
del b # frees memory
out += c
del c # frees memory
out += d
del d # frees memory
out += e
del e # frees memory
return out
# compiled code:
def forward(a, b, c, d, e):
# b, c, d, e can't be freed before end of function
```
This isn't a concern when compiling forward because a, b, c, d, e are all from user code, and should be kept alive. But when compiling backwards, a, b, c, d, e may be intermediate results i.e. activations, that we DO want to clear ASAP to remain on par with eager peak memory.
### Solution
We have encountered similar memory problems in AOTAutograd before, where we adopted the boxed calling convention (wrapping to-be-freed objects in a list), adding list clearing to inductor codegen, and being careful about holding references to elements in the input list. We need to do something similar, but for inputs from the user program (compiled autograd fx graph in this case).
This PR support lists as graphargs/placeholder nodes. When tracing a list of tensors, we create a node for it, and pre-emptively initialize variable trackers for its elements before they are used in the user program. Subsequent uses of those variables will find hits in the lookup table `input_source_to_var`.
With the inputs as a list in the graph args, our compiled code can free inputs just like in the eager case.
```python
def forward(inputs):
# a, b, c, d, e can be freed within the function now
```
Currently, AOT/Inductor flattens list input via [flatten_graph_inputs wrapper](597f479643/torch/_inductor/compile_fx.py (L1454-L1478)), which is why this PR's CI can be green. Additional changes are needed to its runtime wrapper, done in the next PR. The next step is to ensure that we are careful in forwarding the list to inductor codegen without holding additional references.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122353
Approved by: https://github.com/jansel
ghstack dependencies: #123630, #123674
`dynamo.explain()` was updated to return a structure but the docs weren't updated to match.
- Update the docs to use the new API
- Remove some dead code left when `explain` was updated.
- Drive-by: Fix some `nopython` uses that I noticed
- Drive-by: I noticed an ignored error coming from CleanupHook on shutdown - make it check the global before setting it.
Fixes#122573
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122745
Approved by: https://github.com/jansel
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
`unimplemented` is a function that raises an error, so
`raise unimplemented(...)` never reaches the `raise`.
Another related issue is that `raise unimplemented(...) from e`
doesn't attach the exception cause correctly. I fix this by adding
a `from_exc` argument to `unimplemented`.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/122136
Approved by: https://github.com/lezcano
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
List of changes:
- Replace JVP_NESTING by torch._C._functorch.maybe_current_level()
- Remove all increment nesting functions from wrap_fx_proxy_cls
- fwAD.make_dual receives the dual_level as keyword argument
- Add jvp_increment_nesting, set_fwd_grad_enabled and dual_level context managers to dynamo
Pull Request resolved: https://github.com/pytorch/pytorch/pull/119926
Approved by: https://github.com/zou3519
