Manually add libtorch op test

[t-vi]

We want the test to run in integration-gpu in the CI, but currently it is not picked up there and on the CPU, we do not have PyTorch. I would not know why it is not tried on the gpu-enabled CI run.

[t-vi]

So the PyTorch version we are using has the old, incompatible DLPack.
Quite likely this means we cannot enable the libtorch op before we move to PyTorch 1.11.
Would that be feasible?

[t-vi]

For context: pytorch/pytorch#64995

[t-vi]

@masahi Do you think bumping to PyTorch 1.11 would be an option?

[t-vi]

I'm attempting to bump the version in #10794

[masahi]

I'm testing the new docker image in ci-docker-staging. I've hit an error from Keras twice https://ci.tlcpack.ai/blue/organizations/jenkins/tvm/detail/ci-docker-staging/242/pipeline/315, not sure if it is related or flaky. There is also an error from ONNX tests that use PyTorch.

[t-vi]

The keras looks like it's some compat-breaking change somewhere, I don't know if we accidentally (or intentionally) upgraded that...

I'll check the ONNX change, maybe the input has been renamed (I'm not sure that they would be terribly stable unless specified), but likely not before tomorrow.

[masahi]

No worry, I fixed both issues and the test passed https://github.com/apache/tvm/tree/ci-docker-staging. I will send a pr tomorrow

[t-vi]

Awesome! Thank you!

[masahi]

#10849 was merged, this PR is finally unblocked now.

[t-vi]

[2022-04-01T19:22:29.075Z] /usr/lib/gcc/x86_64-linux-gnu/7/../../../x86_64-linux-gnu/libcuda.so: file not recognized: File truncated
[2022-04-01T19:22:29.075Z] collect2: error: ld returned 1 exit status
[2022-04-01T19:22:29.075Z] CMakeFiles/tvm_runtime.dir/build.make:253: recipe for target 'libtvm_runtime.so' failed
[2022-04-01T19:22:29.075Z] make[2]: Leaving directory '/workspace/build'
[2022-04-01T19:22:29.075Z] make[2]: *** [libtvm_runtime.so] Error 1

any ideas what that could be about?

[masahi]

No idea, this happens only when linked with libtorch.so, right?

https://discuss.pytorch.org/t/building-pytorch-from-source-failed-on-ubuntu-16-04/43026 suggests our cuda install is broken, but since CI has passed with PT 1.11, I don't think that's the case.

One thing that could be related is that our ci-gpu is using fairly old cuda - 11.0 according to https://github.com/apache/tvm/blob/main/docker/Dockerfile.ci_gpu#L20. Maybe this is incompatible with the latest libtorch.so? Even if that's the case, I don't get why we didn't get any errors on the CI test.

In the worst case, we can install CPU-version of PT, since we don't need cuda capability for CI purpose.

cc @driazati

[t-vi]

So I wonder if it's that libtorch and tvm try to link to different versions of libcuda...

[masahi]

When we install torch via pip install torch==1.11.0, how do we know which cuda it was built against? Maybe we should explicitly specify the cuda version as in https://pytorch.org/ (pip3 install torch -extra-index-url https://download.pytorch.org/whl/cu113). But a better way is still to install a CPU-only version.

Or we can try updating our NVIDIA container image to update cuda itself (we should do that anyway sooner or later). I don't know what process is required for that.

[t-vi]

How do we know which cuda it was built against?

I think mostly from looking at the CUDA version it advertises on https://pytorch.org/get-started/locally/ (for the current PyTorch CUDA 10.2).
If the problem is only when linking libtvm and libtorch, a CPU-only PyTorch could solve this or maybe just finding a PyTorch enabled CPU instance to build the fallback and run this test on.

[t-vi]

So some of the tests seem to look at whether cuda is available to torch. We could go over these and avoid that - I'm wondering whether the the measure_latency function is used at all btw.

tvm/tests/python/frontend/pytorch/test_forward.py

Line 127 in 41cfd3d

def measure_latency(model, input_shapes, output_shapes, thresh, dryruns=40):

Another idea could be to use a CPU-only PyTorch in the build setup and then use a GPU-enabled one in the testing if the problem is mainly with the linkage of libtvm->libtorch->cuda...

[masahi]

I'm wondering whether the the measure_latency function is used at all btw.

That's a left over from the initial PR from AWS. It is completely irrelevant and should be removed.

We never need GPU-enabled PT for testing purposes. To avoid driver-related problems in the future, we should switch to CPU-only build.

[t-vi]

Thank you. I'll send a PR.

[masahi]

We can come back to this now. Recently when I tried to test PyTorchTVM stuff #8777, I hit an undefined symbol issue from libtorch. So even though we cleared cuda issues, I fear we might encounter another issues.

[t-vi]

I hit an undefined symbol issue from libtorch. So even though we cleared cuda issues, I fear we might encounter another issues.

Was this with libtorch symbols?
I think the libtorch ABI is not terribly stable (to put it mildly) but if we use the exact same libtorch distribution (and my understanding is that we do in the CI), it should work.
I rarely hit this particular problem, because I use a global PyTorch installation for everything, but then I always get missing symbols if I update PyTorch without updating the auxiliary libraries that have extension modules...

[masahi]

It's the same problem as https://discuss.tvm.apache.org/t/can-someone-please-give-me-the-steps-to-use-pt-tvmdsoop/12525, something related to GLIBCXX_USE_CXX11_ABI issues apparently.

[t-vi]

Yeah. So I think the official PyTorch Python packages don't use the "new" C++ API due to Python module conventions buried somewhere...

[t-vi]

So I'm having trouble to reproduce the exact failure on my dev machine, but I use newer cmake (not sure if that matters, but I don't have a good idea as to what that error message wants to tell me...)

[masahi]

but I don't have a good idea as to what that error message wants to tell me...

You mean the error $<COMPILE_LANGUAGE:...> Unknown language. from https://ci.tlcpack.ai/blue/organizations/jenkins/tvm/detail/PR-10758/9/pipeline/? If PT 1.11 requires newer cmake, maybe you can reproduce the error if you use an older cmake?

Note that updating Dockerfile for cmake requires going through another CI image update process. If the cmake version is indeed the problem, I can take care of another update.

[t-vi]

I don't really know if the cmake version is the problem as I have not been able to reproduce it locally nor do I fully understand the error message. So I guess it's nontrivial to find out in the CI if updating cmake helps. :/
If you had any advice, I'd gladly follow it.

[masahi]

No idea either, my cmake-fu is very low unfortunately...

[t-vi]

After quite a bit of work, I have reproduced the failure locally and can confirm that bumping cmake to the version compiled from source does solve the error.

[t-vi]

Of course, if a bump of the ubuntu base were imminent, that could be an alternative.

[masahi]

I see, I don't know if we are updating ubuntu any time soon (cc @driazati), so can you send docker/Dockerfile.ci_gpu change in a separate PR?

[driazati]

sorry for my delays, I was able to repro the error using tests/scripts/ci.py:

gh pr checkout -f 10758
# errors out
python tests/scripts/ci.py gpu

upgrading to cmake 3.11.4 (via this patch to ci.py) seems to fix it and the build finishes successfully though

diff --git a/tests/scripts/ci.py b/tests/scripts/ci.py
index c0ce085ff..4ee9725e7 100755
--- a/tests/scripts/ci.py
+++ b/tests/scripts/ci.py
@@ -370,10 +370,22 @@ def generate_command(
         if precheck is not None:
             precheck()
 
+        cmake_stuff = [
+            "sudo apt remove -y cmake",
+            "rm -rf CMake",
+            "git clone --branch v3.11.4 https://github.com/Kitware/CMake.git --depth=1",
+            "pushd CMake",
+            "./configure --parallel=24",
+            "make -j24",
+            "sudo ln -s $(pwd)/bin/cmake /usr/bin/cmake",
+            "popd",
+            "cmake --version",
+        ]
+
         if skip_build:
             scripts = []
         else:
-            scripts = [
+            scripts = cmake_stuff + [
                 f"./tests/scripts/task_config_build_{name}.sh {get_build_dir(name)}",
                 f"./tests/scripts/task_build.py --build-dir {get_build_dir(name)}",
                 # This can be removed once https://github.com/apache/tvm/pull/10257

then re-running

tests/scripts/ci.py gpu

so upgrading cmake to 3.11.4 in CI seems like the best way to go (we're on 3.10 right now), so @t-vi if ubuntu_install_cmake_source.sh builds cmake 3.11.4 that'd be good, and we'll need another (😢) docker image update as well

[t-vi]

I've submitted the build with the new cmake. Thank you for patiently helping me.

[t-vi]

So it seems that the libtorch linked into TVM and the libtorch that the PyTorch wants are incompatible now. :/
I will check if it is possible to only have the linked-to-libtorch symbols locally visible in the hope that they don't interfere then, but I'm not sure that that'll work.