Remove unnecessary cuda sync for better perf

[Gasoonjia]

Stack from ghstack (oldest at bottom):

• -> Remove unnecessary cuda sync for better perf #17315
• ping bump torchcodec #17324

Right now we always do cudasync before existing cudabackend.execution(). However we only need that when copying data from gpu to cpu; any actions happen inside a same stream do not need explicit sync.

Differential Revision: D92193164

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/executorch/17315

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❗ 1 Active SEVs

There are 1 currently active SEVs. If your PR is affected, please view them below:

• Lint/Mac jobs intermittently fail

❌ 7 New Failures

As of commit 793500d with merge base 4930e7c ():

NEW FAILURES - The following jobs have failed:

• Test CUDA Builds / test-model-cuda-e2e (nvidia, parakeet-tdt, quantized-int4-tile-packed) / linux-job (gh)
  ##[error]Response status code does not indicate success: 429 (Too Many Requests).
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-large-v3-turbo, non-quantized) / linux-job (gh)
  RuntimeError: Command docker exec -t 6a81797802876fe6fd602c4cda0cac7337f0365c5fd9dd25db7876752908963d /exec failed with exit code 1
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-large-v3-turbo, quantized-int4-tile-packed) / linux-job (gh)
  RuntimeError: Command docker exec -t 1f72b0da04a0e2e4b9d08b1d678aed7d70c79672eaa877ac9c63f005539db6d1 /exec failed with exit code 1
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-large-v3-turbo, quantized-int4-weight-only) / linux-job (gh)
  RuntimeError: Command docker exec -t 6073b41c240c2c1cf39aa9e11eb82d45e7a5df6cc8dfbb6a41623ad75100c494 /exec failed with exit code 1
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-small, non-quantized) / linux-job (gh)
  RuntimeError: Command docker exec -t 33c800b16f98dcfb555b501d672a9c5f1f9e31ba5ca9669f05a9176a4d2bb239 /exec failed with exit code 1
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-small, quantized-int4-tile-packed) / linux-job (gh)
  RuntimeError: Command docker exec -t 3b22905c33aa454cdaa049f86751cb607486da8c13cdb221d19576335d77b502 /exec failed with exit code 1
• Test CUDA Builds / test-model-cuda-e2e (openai, whisper-small, quantized-int4-weight-only) / linux-job (gh)
  RuntimeError: Command docker exec -t 5ba1244ea5dbe22504e285a1cfd3385ff7c2aec71e02041fba1de5c6482687a5 /exec failed with exit code 1

This comment was automatically generated by Dr. CI and updates every 15 minutes.

[github-actions]

This PR needs a release notes: label

If your change should be included in the release notes (i.e. would users of this library care about this change?), please use a label starting with release notes:. This helps us keep track and include your important work in the next release notes.

To add a label, you can comment to pytorchbot, for example
@pytorchbot label "release notes: none"

For more information, see
https://github.com/pytorch/pytorch/wiki/PyTorch-AutoLabel-Bot#why-categorize-for-release-notes-and-how-does-it-work.