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[pytorch] Accelerate indexing_backward_kernel with duplicates#99441

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[pytorch] Accelerate indexing_backward_kernel with duplicates#99441
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@valentinandrei valentinandrei commented Apr 18, 2023

By knowing the stride value ahead of time, we can simplify the kernel code as follows:

If stride == 1 we can use the whole warp to reduce the gradients
If stride < warp_size we don't need the internal while (start_feature < stride) loop as blockDim.x is always 32

This changes improve the performance of the kernel when duplicates are present and do not affect the performance with low amount of duplicates. The implementation is deterministic.

The proposed implementation uses opmath_t to accumulate in registers the gradient values so when using FP16/BF16 it may overflow if the number of elements is large. This is different from the initial implementation who accumulates in scalar_t and does not overflow. In addition, when the stride is 1, we are using warp shuffles to sum the gradient so the order of the addition is slightly different than a reference implementation which causes some minor numerical differences when compared to a reference.

TEST CODE:

# The first element is the number of iterations.
# The second represents the number of unique elements. If
# set to 0, the number of unique elements is equal to the
# number of elements.
# The remaining elements are the tensor dimensions.

basic_indexing_tests = [
    [10, 0, 12345],
    [10, 4, 12345],
    [10, 16, 512, 512, 32],
    [10, 0, 4, 4],
    [10, 0, 32, 32],
    [10, 8, 32, 32],
    [10, 8, 64, 32, 16],
    [10, 0, 64, 32, 16],
    [10, 16, 512, 512, 32],
    [10, 0, 675, 999, 13],
    [10, 0, 123, 456, 31],
    [10, 0, 512, 512, 32],
    [10, 4, 512, 512, 32],
    [10, 2, 512, 512, 32],
    [10, 0, 128, 128, 16, 16],
    [10, 8, 128, 126, 16, 16],
    [10, 4, 128, 126, 16, 16],
    [10, 0, 64, 64, 16, 16, 16],
    [10, 8, 64, 64, 16, 16, 16],
    [10, 2, 64, 64, 16, 16, 16],
    [10, 1, 64, 64, 16, 16, 16],
]


def run_basic_indexing_on_device(x, index, expected, device_string, iters):
    x_dev = x.to(device_string)
    x_dev = x_dev.detach().requires_grad_()
    index_dev = index.to(device_string)

    # Run backward pass; keep gradients and measure time
    torch.cuda.synchronize()
    t_bw_s = time()
    for _ in range(iters):
        y = x_dev[index_dev]
        z = y.sum()
        z.backward()
    torch.cuda.synchronize()
    t_bw_s = (time() - t_bw_s) / iters

    return (x_dev.grad, t_bw_s)


def run_basic_indexing_test(test_input):
    tensor_size = tuple(test_input[:5])
    niters = test_input[0]
    num_unique = test_input[1]
    tensor_size = tuple(test_input[2:])

    numel = 1
    for dim in tensor_size:
        numel *= dim
    if num_unique == 0:
        num_unique = numel

    index = torch.randint(0, num_unique, tensor_size, dtype=torch.long, device="cpu")
    x = torch.randn((numel,), dtype=torch.float32, device="cuda")

    index = index.detach()
    x = x.detach().requires_grad_()

    (cpu_grad, t_bw_cpu) = run_basic_indexing_on_device(x, index, numel / 2, "cpu", 1)
    (gpu_grad, t_bw_gpu) = run_basic_indexing_on_device(x, index, numel / 2, "cuda", 1)

    max_delta = torch.max(torch.abs(cpu_grad - gpu_grad.to("cpu")))
    missmatches = torch.nonzero(torch.abs(cpu_grad - gpu_grad.to("cpu")))

    (gpu_grad_perf, t_gpu) = run_basic_indexing_on_device(
        x, index, numel / 2, "cuda", niters
    )

    print(
        "test = {}, delta = {:.5f}, missmatches = {} duration_ms = {:.3f}".format(
            tuple(test_input), max_delta, missmatches, t_gpu * 1000.0
        )
    )

    if torch.numel(missmatches) > 0:
        print("cpu grad = {}", cpu_grad[missmatches])
        print("gpu grad = {}", gpu_grad[missmatches])

RESULTS:

Default Implementation

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.726
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.867
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.514
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.689
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.547
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.537
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.199
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.584
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.055
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.411
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.419
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.048
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.633
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 606.403
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4.099
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 76.813
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.760
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.547
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 317.583
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1204.800
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2412.133

Small Stride Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.904
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.156
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 308.878
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.566
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.540
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.550
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.868
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.656
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.856
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.624
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.837
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.274
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1127.040
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2123.942
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.282
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 288.997
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 547.267
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 12.844
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1178.934
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4262.042
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8172.318

Stride 1 Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.692
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.834
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 81.023
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.631
test = (100, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.491
test = (100, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.477
test = (50, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.561
test = (50, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.516
test = (16, 10, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 126.455
test = (10, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.238
test = (10, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.520
test = (10, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 7.854
test = (10, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 306.327
test = (10, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 610.498
test = (5, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.684
test = (5, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 75.604
test = (5, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.679
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.525
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 315.095
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1214.715

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@pytorchbot label "topic: performance"

@pytorch-bot pytorch-bot Bot added the topic: performance topic category label Apr 21, 2023
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ngimel commented May 1, 2023

@pytorchbot merge

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@ngimel I'd suggest reverting this PR, since it's consistently breaking ROCm CI as seen here: https://hud.pytorch.org/ci/pytorch/pytorch/main?name_filter=rocm

I have added some comments on this PR where I think the code is very CUDA-specific.

cc @kit1980 @malfet

Comment thread aten/src/ATen/native/cuda/Indexing.cu
}
WARP_SYNC();
for (int offset = 16; offset > 0; offset /= 2) {
gradient += WARP_SHFL_DOWN(gradient, offset);
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@ngimel Would this work correctly for a warp_size of 64 (AMD GPUs)?

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Yeah we shouldn't hardcode offset here, you are right. Again, we'd need compile-time-known warp width.

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ngimel commented May 2, 2023

Sorry about that @jithunnair-amd the tests were clean.

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ngimel commented May 2, 2023

@pytorchbot revert -c nosignal -m "breaks ROCM"

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@valentinandrei your PR has been successfully reverted.

pytorchmergebot added a commit that referenced this pull request May 2, 2023
valentinandrei pushed a commit to valentinandrei/pytorch that referenced this pull request May 2, 2023
valentinandrei added a commit to valentinandrei/pytorch that referenced this pull request May 2, 2023
valentinandrei added a commit to valentinandrei/pytorch that referenced this pull request May 2, 2023
…code that broke ROCm CI"

This reverts commit 1eb0fb7.
valentinandrei added a commit to valentinandrei/pytorch that referenced this pull request May 2, 2023
pytorchmergebot pushed a commit that referenced this pull request May 3, 2023
…attempt 2) (#100505)

By knowing the stride value ahead of time, we can simplify the kernel code as follows:

If stride == 1 we can use the whole warp to reduce the gradients
If stride < warp_size we don't need the internal while (start_feature < stride) loop as blockDim.x is always 32

This changes improve the performance of the kernel when duplicates are present and do not affect the performance with low amount of duplicates. The implementation is deterministic.

The proposed implementation uses opmath_t to accumulate in registers the gradient values so when using FP16/BF16 it may overflow if the number of elements is large. This is different from the initial implementation who accumulates in scalar_t and does not overflow. In addition, when the stride is 1, we are using warp shuffles to sum the gradient so the order of the addition is slightly different than a reference implementation which causes some minor numerical differences when compared to a reference.

TEST CODE:

```
# The first element is the number of iterations.
# The second represents the number of unique elements. If
# set to 0, the number of unique elements is equal to the
# number of elements.
# The remaining elements are the tensor dimensions.

basic_indexing_tests = [
    [10, 0, 12345],
    [10, 4, 12345],
    [10, 16, 512, 512, 32],
    [10, 0, 4, 4],
    [10, 0, 32, 32],
    [10, 8, 32, 32],
    [10, 8, 64, 32, 16],
    [10, 0, 64, 32, 16],
    [10, 16, 512, 512, 32],
    [10, 0, 675, 999, 13],
    [10, 0, 123, 456, 31],
    [10, 0, 512, 512, 32],
    [10, 4, 512, 512, 32],
    [10, 2, 512, 512, 32],
    [10, 0, 128, 128, 16, 16],
    [10, 8, 128, 126, 16, 16],
    [10, 4, 128, 126, 16, 16],
    [10, 0, 64, 64, 16, 16, 16],
    [10, 8, 64, 64, 16, 16, 16],
    [10, 2, 64, 64, 16, 16, 16],
    [10, 1, 64, 64, 16, 16, 16],
]

def run_basic_indexing_on_device(x, index, expected, device_string, iters):
    x_dev = x.to(device_string)
    x_dev = x_dev.detach().requires_grad_()
    index_dev = index.to(device_string)

    # Run backward pass; keep gradients and measure time
    torch.cuda.synchronize()
    t_bw_s = time()
    for _ in range(iters):
        y = x_dev[index_dev]
        z = y.sum()
        z.backward()
    torch.cuda.synchronize()
    t_bw_s = (time() - t_bw_s) / iters

    return (x_dev.grad, t_bw_s)

def run_basic_indexing_test(test_input):
    tensor_size = tuple(test_input[:5])
    niters = test_input[0]
    num_unique = test_input[1]
    tensor_size = tuple(test_input[2:])

    numel = 1
    for dim in tensor_size:
        numel *= dim
    if num_unique == 0:
        num_unique = numel

    index = torch.randint(0, num_unique, tensor_size, dtype=torch.long, device="cpu")
    x = torch.randn((numel,), dtype=torch.float32, device="cuda")

    index = index.detach()
    x = x.detach().requires_grad_()

    (cpu_grad, t_bw_cpu) = run_basic_indexing_on_device(x, index, numel / 2, "cpu", 1)
    (gpu_grad, t_bw_gpu) = run_basic_indexing_on_device(x, index, numel / 2, "cuda", 1)

    max_delta = torch.max(torch.abs(cpu_grad - gpu_grad.to("cpu")))
    missmatches = torch.nonzero(torch.abs(cpu_grad - gpu_grad.to("cpu")))

    (gpu_grad_perf, t_gpu) = run_basic_indexing_on_device(
        x, index, numel / 2, "cuda", niters
    )

    print(
        "test = {}, delta = {:.5f}, missmatches = {} duration_ms = {:.3f}".format(
            tuple(test_input), max_delta, missmatches, t_gpu * 1000.0
        )
    )

    if torch.numel(missmatches) > 0:
        print("cpu grad = {}", cpu_grad[missmatches])
        print("gpu grad = {}", gpu_grad[missmatches])
```

RESULTS:

```
Default Implementation

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.726
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.867
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.514
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.689
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.547
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.537
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.199
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.584
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.055
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.411
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.419
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.048
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.633
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 606.403
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4.099
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 76.813
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.760
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.547
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 317.583
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1204.800
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2412.133

Small Stride Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.904
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.156
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 308.878
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.566
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.540
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.550
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.868
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.656
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.856
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.624
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.837
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.274
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1127.040
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2123.942
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.282
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 288.997
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 547.267
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 12.844
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1178.934
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4262.042
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8172.318

Stride 1 Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.692
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.834
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 81.023
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.631
test = (100, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.491
test = (100, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.477
test = (50, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.561
test = (50, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.516
test = (16, 10, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 126.455
test = (10, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.238
test = (10, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.520
test = (10, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 7.854
test = (10, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 306.327
test = (10, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 610.498
test = (5, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.684
test = (5, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 75.604
test = (5, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.679
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.525
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 315.095
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1214.715
```

Pull Request resolved: #100505
Approved by: https://github.com/ngimel
laurentdupin pushed a commit to laurentdupin/pytorch that referenced this pull request Apr 25, 2026
…h#99441)

By knowing the stride value ahead of time, we can simplify the kernel code as follows:

If `stride == 1` we can use the whole warp to reduce the gradients
If `stride < warp_size` we don't need the internal `while (start_feature < stride)` loop as `blockDim.x` is always 32

This changes improve the performance of the kernel when duplicates are present and do not affect the performance with low amount of duplicates. The implementation is deterministic.

The proposed implementation uses `opmath_t` to accumulate in registers the gradient values so when using FP16/BF16 it may overflow if the number of elements is large. This is different from the initial implementation who accumulates in `scalar_t` and does not overflow. In addition, when the stride is 1, we are using warp shuffles to sum the gradient so the order of the addition is slightly different than a reference implementation which causes some minor numerical differences when compared to a reference.

TEST CODE:

```
# The first element is the number of iterations.
# The second represents the number of unique elements. If
# set to 0, the number of unique elements is equal to the
# number of elements.
# The remaining elements are the tensor dimensions.

basic_indexing_tests = [
    [10, 0, 12345],
    [10, 4, 12345],
    [10, 16, 512, 512, 32],
    [10, 0, 4, 4],
    [10, 0, 32, 32],
    [10, 8, 32, 32],
    [10, 8, 64, 32, 16],
    [10, 0, 64, 32, 16],
    [10, 16, 512, 512, 32],
    [10, 0, 675, 999, 13],
    [10, 0, 123, 456, 31],
    [10, 0, 512, 512, 32],
    [10, 4, 512, 512, 32],
    [10, 2, 512, 512, 32],
    [10, 0, 128, 128, 16, 16],
    [10, 8, 128, 126, 16, 16],
    [10, 4, 128, 126, 16, 16],
    [10, 0, 64, 64, 16, 16, 16],
    [10, 8, 64, 64, 16, 16, 16],
    [10, 2, 64, 64, 16, 16, 16],
    [10, 1, 64, 64, 16, 16, 16],
]

def run_basic_indexing_on_device(x, index, expected, device_string, iters):
    x_dev = x.to(device_string)
    x_dev = x_dev.detach().requires_grad_()
    index_dev = index.to(device_string)

    # Run backward pass; keep gradients and measure time
    torch.cuda.synchronize()
    t_bw_s = time()
    for _ in range(iters):
        y = x_dev[index_dev]
        z = y.sum()
        z.backward()
    torch.cuda.synchronize()
    t_bw_s = (time() - t_bw_s) / iters

    return (x_dev.grad, t_bw_s)

def run_basic_indexing_test(test_input):
    tensor_size = tuple(test_input[:5])
    niters = test_input[0]
    num_unique = test_input[1]
    tensor_size = tuple(test_input[2:])

    numel = 1
    for dim in tensor_size:
        numel *= dim
    if num_unique == 0:
        num_unique = numel

    index = torch.randint(0, num_unique, tensor_size, dtype=torch.long, device="cpu")
    x = torch.randn((numel,), dtype=torch.float32, device="cuda")

    index = index.detach()
    x = x.detach().requires_grad_()

    (cpu_grad, t_bw_cpu) = run_basic_indexing_on_device(x, index, numel / 2, "cpu", 1)
    (gpu_grad, t_bw_gpu) = run_basic_indexing_on_device(x, index, numel / 2, "cuda", 1)

    max_delta = torch.max(torch.abs(cpu_grad - gpu_grad.to("cpu")))
    missmatches = torch.nonzero(torch.abs(cpu_grad - gpu_grad.to("cpu")))

    (gpu_grad_perf, t_gpu) = run_basic_indexing_on_device(
        x, index, numel / 2, "cuda", niters
    )

    print(
        "test = {}, delta = {:.5f}, missmatches = {} duration_ms = {:.3f}".format(
            tuple(test_input), max_delta, missmatches, t_gpu * 1000.0
        )
    )

    if torch.numel(missmatches) > 0:
        print("cpu grad = {}", cpu_grad[missmatches])
        print("gpu grad = {}", gpu_grad[missmatches])
```

RESULTS:

```
Default Implementation

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.726
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.867
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.514
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.689
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.547
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.537
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.199
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.584
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.055
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.411
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.419
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.048
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.633
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 606.403
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4.099
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 76.813
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.760
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.547
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 317.583
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1204.800
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2412.133

Small Stride Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.904
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.156
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 308.878
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.566
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.540
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.550
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.868
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.656
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.856
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.624
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.837
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.274
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1127.040
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2123.942
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.282
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 288.997
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 547.267
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 12.844
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1178.934
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4262.042
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8172.318

Stride 1 Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.692
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.834
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 81.023
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.631
test = (100, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.491
test = (100, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.477
test = (50, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.561
test = (50, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.516
test = (16, 10, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 126.455
test = (10, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.238
test = (10, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.520
test = (10, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 7.854
test = (10, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 306.327
test = (10, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 610.498
test = (5, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.684
test = (5, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 75.604
test = (5, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.679
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.525
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 315.095
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1214.715
```
Pull Request resolved: pytorch#99441
Approved by: https://github.com/ngimel
laurentdupin pushed a commit to laurentdupin/pytorch that referenced this pull request Apr 25, 2026
laurentdupin pushed a commit to laurentdupin/pytorch that referenced this pull request Apr 25, 2026
…ch#99441 attempt 2) (pytorch#100505)

By knowing the stride value ahead of time, we can simplify the kernel code as follows:

If stride == 1 we can use the whole warp to reduce the gradients
If stride < warp_size we don't need the internal while (start_feature < stride) loop as blockDim.x is always 32

This changes improve the performance of the kernel when duplicates are present and do not affect the performance with low amount of duplicates. The implementation is deterministic.

The proposed implementation uses opmath_t to accumulate in registers the gradient values so when using FP16/BF16 it may overflow if the number of elements is large. This is different from the initial implementation who accumulates in scalar_t and does not overflow. In addition, when the stride is 1, we are using warp shuffles to sum the gradient so the order of the addition is slightly different than a reference implementation which causes some minor numerical differences when compared to a reference.

TEST CODE:

```
# The first element is the number of iterations.
# The second represents the number of unique elements. If
# set to 0, the number of unique elements is equal to the
# number of elements.
# The remaining elements are the tensor dimensions.

basic_indexing_tests = [
    [10, 0, 12345],
    [10, 4, 12345],
    [10, 16, 512, 512, 32],
    [10, 0, 4, 4],
    [10, 0, 32, 32],
    [10, 8, 32, 32],
    [10, 8, 64, 32, 16],
    [10, 0, 64, 32, 16],
    [10, 16, 512, 512, 32],
    [10, 0, 675, 999, 13],
    [10, 0, 123, 456, 31],
    [10, 0, 512, 512, 32],
    [10, 4, 512, 512, 32],
    [10, 2, 512, 512, 32],
    [10, 0, 128, 128, 16, 16],
    [10, 8, 128, 126, 16, 16],
    [10, 4, 128, 126, 16, 16],
    [10, 0, 64, 64, 16, 16, 16],
    [10, 8, 64, 64, 16, 16, 16],
    [10, 2, 64, 64, 16, 16, 16],
    [10, 1, 64, 64, 16, 16, 16],
]

def run_basic_indexing_on_device(x, index, expected, device_string, iters):
    x_dev = x.to(device_string)
    x_dev = x_dev.detach().requires_grad_()
    index_dev = index.to(device_string)

    # Run backward pass; keep gradients and measure time
    torch.cuda.synchronize()
    t_bw_s = time()
    for _ in range(iters):
        y = x_dev[index_dev]
        z = y.sum()
        z.backward()
    torch.cuda.synchronize()
    t_bw_s = (time() - t_bw_s) / iters

    return (x_dev.grad, t_bw_s)

def run_basic_indexing_test(test_input):
    tensor_size = tuple(test_input[:5])
    niters = test_input[0]
    num_unique = test_input[1]
    tensor_size = tuple(test_input[2:])

    numel = 1
    for dim in tensor_size:
        numel *= dim
    if num_unique == 0:
        num_unique = numel

    index = torch.randint(0, num_unique, tensor_size, dtype=torch.long, device="cpu")
    x = torch.randn((numel,), dtype=torch.float32, device="cuda")

    index = index.detach()
    x = x.detach().requires_grad_()

    (cpu_grad, t_bw_cpu) = run_basic_indexing_on_device(x, index, numel / 2, "cpu", 1)
    (gpu_grad, t_bw_gpu) = run_basic_indexing_on_device(x, index, numel / 2, "cuda", 1)

    max_delta = torch.max(torch.abs(cpu_grad - gpu_grad.to("cpu")))
    missmatches = torch.nonzero(torch.abs(cpu_grad - gpu_grad.to("cpu")))

    (gpu_grad_perf, t_gpu) = run_basic_indexing_on_device(
        x, index, numel / 2, "cuda", niters
    )

    print(
        "test = {}, delta = {:.5f}, missmatches = {} duration_ms = {:.3f}".format(
            tuple(test_input), max_delta, missmatches, t_gpu * 1000.0
        )
    )

    if torch.numel(missmatches) > 0:
        print("cpu grad = {}", cpu_grad[missmatches])
        print("gpu grad = {}", gpu_grad[missmatches])
```

RESULTS:

```
Default Implementation

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.726
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.867
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.514
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.689
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.547
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.537
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.199
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.584
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 80.055
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.411
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.419
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.048
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.633
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 606.403
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4.099
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 76.813
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.760
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.547
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 317.583
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1204.800
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2412.133

Small Stride Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.904
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.156
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 308.878
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.566
test = (1, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.540
test = (1, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.550
test = (1, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2.868
test = (1, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.656
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 307.856
test = (1, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.624
test = (1, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.837
test = (1, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 6.274
test = (1, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1127.040
test = (1, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 2123.942
test = (1, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.282
test = (1, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 288.997
test = (1, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 547.267
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 12.844
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1178.934
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 4262.042
test = (1, 1, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8172.318

Stride 1 Kernel Version

test = (1, 0, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.692
test = (1, 4, 12345), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.834
test = (1, 16, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 81.023
test = (1, 0, 4, 4), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.631
test = (100, 0, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.491
test = (100, 8, 32, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.477
test = (50, 8, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.561
test = (50, 0, 64, 32, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 0.516
test = (16, 10, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 126.455
test = (10, 0, 675, 999, 13), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 8.238
test = (10, 0, 123, 456, 31), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1.520
test = (10, 0, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 7.854
test = (10, 4, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 306.327
test = (10, 2, 512, 512, 32), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 610.498
test = (5, 0, 128, 128, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 3.684
test = (5, 8, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 75.604
test = (5, 4, 128, 126, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 148.679
test = (1, 0, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 16.525
test = (1, 8, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 315.095
test = (1, 2, 64, 64, 16, 16, 16), delta = 0.00000, missmatches = tensor([], size=(0, 1), dtype=torch.int64) duration_ms = 1214.715
```

Pull Request resolved: pytorch#100505
Approved by: https://github.com/ngimel
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