Conversation
On some platforms the device's 8-byte write of a profiling tag's recorded timestamp also rewrites the rest of the aligned 64-byte block around it, with stale contents. It only shows up when the two happen at the same time: the device landing a timestamp write while the host writes the event state sitting next to it, which is what recycling a pooled event for a new recording does. Those host writes are then lost - including the flag marking the event as timestamp-recording, so the fresh recording reports UR_RESULT_ERROR_PROFILING_INFO_NOT_AVAILABLE. Give the timestamp a 64-byte block of its own to work around this. Note there is no race on the timestamp itself: recordings sharing a destination are serialized - by the queue for an in-order queue, and by the barriers SYCL brackets each tag with for an out-of-order one - so the last write to land is the current recording's. Driver issue is tracked as GSD-13449. Assisted-By: Claude
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
1 participant
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
On some platforms the device's 8-byte write of a profiling tag's recorded timestamp also rewrites the rest of the aligned 64-byte block around it, with stale contents. It only shows up when the two happen at the same time: the device landing a timestamp write while the host writes the event state sitting next to it, which is what recycling a pooled event for a new recording does. Those host writes are then lost - including the flag marking the event as timestamp-recording, so the fresh recording reports UR_RESULT_ERROR_PROFILING_INFO_NOT_AVAILABLE.
Give the timestamp a 64-byte block of its own to work around this. Note there is no race on the timestamp itself: recordings sharing a destination are serialized - by the queue for an in-order queue, and by the barriers for an out-of-order one.
Driver issue is tracked as GSD-13449.
Assisted-By: Claude