GraphTask holds metadata needed for a single execution of backward(), it is 1:1 with backward calls, at least for compiled autograd. It is used for certain torch._C global autograd state APIs.
In SAC, we use torch._C._current_graph_task_id() as a dict key to store information during unpack hook execution: a5fb07af27/torch/utils/checkpoint.py (L1128)
If we don't set an active task, it will randomize the key, and will do its logic as if each unpacked tensor was from a different graph task
a5fb07af27/torch/utils/checkpoint.py (L1112-L1115)
The sketchy part of this PR is that in eager autograd, GraphTask is mutated during execution. But inspecting the struct, the mutation seems to only be used to communicate between autograd threads (created when multiple devices are involved) or for deprecated uses. We shouldn't run into the mutation case at all in compiled autograd. Also, only the graph task id is accessible from python hooks.
FIXES https://github.com/pytorch/pytorch/issues/142862
Pull Request resolved: https://github.com/pytorch/pytorch/pull/143108
Approved by: https://github.com/jansel, https://github.com/albanD
Thanks @awgu for raising this issue and the small repro
From offline discussion with @albanD, in the case where a forward returns multiple outputs with different devices, we'd want to select the ready queue based on the device of the first one. Even though this is somewhat arbitrary, we prefer this over deciding which ready queue to push based on whichever input buffer's we happen to compute last, which can vary depending on more factors and thus be harder to reason about. This is in theory bc-breaking, but it seems unlikely that someone would depend on this behavior.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/135633
Approved by: https://github.com/albanD
Summary:
`-Wunused-exception-parameter` has identified an unused exception parameter. This diff removes it.
This:
```
try {
...
} catch (exception& e) {
// no use of e
}
```
should instead be written as
```
} catch (exception&) {
```
If the code compiles, this is safe to land.
Test Plan: Sandcastle
Reviewed By: palmje
Differential Revision: D55548497
Pull Request resolved: https://github.com/pytorch/pytorch/pull/123056
Approved by: https://github.com/Skylion007
The main thread and the autograd one are latency critical threads. They launch CPU/GPU/Accelerator kernels and if for some reason they get preempted, the rank can become a straggler in a distributed training application. By naming these threads we can debug performance issues that impact the latency sensitive threads.
I used Kineto traces to verify if the thread names were propagated:
<img width="851" alt="Screenshot 2024-03-04 at 3 07 43 PM" src="https://github.com/pytorch/pytorch/assets/23515689/68b4a09c-b8e5-4f14-a5c0-6593f866c03f">
Also:
```
nvidia-smi
+-----------------------------------------------------------------------------+
| Processes: |
| GPU GI CI PID Type Process name GPU Memory |
| ID ID Usage |
|=============================================================================|
| 0 N/A N/A 3065920 C ...me#python#py_version_3_10 1968MiB |
| 1 N/A N/A 3065926 C ...me#python#py_version_3_10 1978MiB |
| 2 N/A N/A 3065930 C ...me#python#py_version_3_10 2084MiB |
| 3 N/A N/A 3065936 C ...me#python#py_version_3_10 2016MiB |
| 4 N/A N/A 3065939 C ...me#python#py_version_3_10 1998MiB |
| 5 N/A N/A 3065943 C ...me#python#py_version_3_10 2070MiB |
| 6 N/A N/A 3065948 C ...me#python#py_version_3_10 2026MiB |
| 7 N/A N/A 3065952 C ...me#python#py_version_3_10 2070MiB |
+-----------------------------------------------------------------------------+
[me@myhost ~]$ ps -T -p 3065920
PID SPID TTY TIME CMD
3065920 3065920 pts/14 00:01:04 pt_main_thread
...
3065920 3092181 pts/14 00:00:40 pt_autograd_d0
3065920 3092182 pts/14 00:00:00 pt_autograd_d1
3065920 3092183 pts/14 00:00:00 pt_autograd_d2
3065920 3092184 pts/14 00:00:00 pt_autograd_d3
3065920 3092185 pts/14 00:00:00 pt_autograd_d4
3065920 3092186 pts/14 00:00:00 pt_autograd_d5
3065920 3092187 pts/14 00:00:00 pt_autograd_d6
3065920 3092188 pts/14 00:00:00 pt_autograd_d7
...
```
Pull Request resolved: https://github.com/pytorch/pytorch/pull/121170
Approved by: https://github.com/albanD
Fixes#50051.
This PR is based on #50320 and I address the last feedback.
On Windows it is enabled by default. Can be enabled or disabled via USE_CUSTOM_TERMINATE env variable.
This PR adds support for overriding the terminate handler in order to log uncaught exceptions in the threads.
If an exception is thrown and not caught, it will print <Unhandled exception caught in c10/util/AbortHandler.h>
The point of doing this is that in issue #50051, exceptions were thrown but not logged. With this logging system it will be easier to debug it in the future.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/101332
Approved by: https://github.com/albanD, https://github.com/malfet
The existing try-catch doesn't work because it doesn't call err.persist(). This is in contrast to the try-catch for evaluate_function which does work because it calls into python_engine's thread_on_exception which calls persist.
Calling persist on a python_error stashes the PyErr state from the thread-local PyThreadState onto the python_error object, so that when this error object is stored onto the future and passed back to the calling cpu thread, python_engine's execute try-catch can then err.restore() the error state. Finally, the python_engine's execute would re-raise so that this is re-caught by the HANDLE_TH_ERRORS macro.
Fixes https://github.com/pytorch/pytorch/issues/75750
Pull Request resolved: https://github.com/pytorch/pytorch/pull/113702
Approved by: https://github.com/albanD
Fixes#106555
There was bug where the multithreading check would fire because of the
`compiled_autograd.disable()` calls in AotAutograd, even though compiled
autograd was already disabled, so that call was doing nothing.
Pull Request resolved: https://github.com/pytorch/pytorch/pull/106621
Approved by: https://github.com/yanboliang
This branch:
1) converts the autograd tape into an FX graph
2) caches that conversion using a "shadow" graph
3) compiles and runs the generated FX graph instead of the normal autograd
What works currently:
1) Caching, capture, and initial integration
2) Backwards hooks
3) Inlining AotAutograd generated subgraphs
4) torch.compiling the generated FX graph
5) Auto-detecting dynamic shapes based on changes
Future work
1) Larger scale testing
1) Boxed calling convention, so memory can be freed incrementally
1) Support hooks on SavedTensor
1) Additional testing by running eager autograd tests under compiled_autograd.enable()
Pull Request resolved: https://github.com/pytorch/pytorch/pull/103822
Approved by: https://github.com/ezyang, https://github.com/albanD
