Reduce the device bubble introduced by heavy loop synchronization in coalesced fetch/release(z3_leaf_module) #6694
+67
−39
Conversation
This file contains 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
…pSpeed into z3_coalesced_fetch
inkcherry
force-pushed
the
reduce_coalesced_fetch_bubble
branch
2 times, most recently
from
d9c3687 to
663e637
Compare
|
Hi , @tjruwase. Some models use a large number of MoE experts, but the total number of parameters for MoE remains unchanged. This PR handles such cases as a whole to optimize memory management and reduce bubbles caused by long loops. when Do you have any suggestions? |
tjruwase
reviewed
Dec 24, 2024
| for part_to_copy in partitions: | ||
| if not get_accelerator().is_synchronized_device(): | ||
| part_to_copy.record_stream(get_accelerator().current_stream()) | ||
| if handle_dependency: |
There was a problem hiding this comment.
Would the following not work?
Suggested change
| if handle_dependency: | |
| if handle_dependency and not get_accelerator().is_synchronized_device() : |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
depend on #6649
When performing fetch/release operations on Z3 leaf modules, the loop time is excessively long in fine-grained module. Compared to non-leaf modules, Z3 leaf modules may include a larger number of parameters. Although each loop unit does not consume much time, the overall loop length can be significant.
The fetch time is impacted by:
Post-allgather operations (narrow， slice ，cat, difficult to avoid)
Memory pressure（record_stream/fetch event create&sync）
The release time is impacted by:
slice
Free parameter record_stream
Considering the fine-grained leaf modules, where each parameter is relatively small, we can treat the parameters within each leaf module as a unified entity to handle memory pressure. This approach can approximately halve the CPU time required for fetch/release operations.