ZIO: Remove READY pipeline stage from root ZIOs #15398
Merged
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
amotin
force-pushed
the
zio_root
branch
3 times, most recently
from
a517a2b to
d0801d7
Compare
zio_root() has no arguments for ready callback or parent ZIO. Except one recent case in ZIL code if root ZIOs ever have a parent it is also a root ZIO. It means we do not need READY pipeline stage for them, which takes some time to process, but even more time to wait for the children and be woken by them, and both for no good reason. The most visible effect of this change is that it avoids one taskq wakeup per ZIL block written, previously used to run zio_ready() for lwb_root_zio and skipped now. Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc.
behlendorf
approved these changes
Oct 20, 2023
behlendorf
added
Status: Accepted
amotin
added
the
Type: Performance
lundman
pushed a commit
to openzfsonwindows/openzfs
that referenced
this pull request
Dec 12, 2023
zio_root() has no arguments for ready callback or parent ZIO. Except one recent case in ZIL code if root ZIOs ever have a parent it is also a root ZIO. It means we do not need READY pipeline stage for them, which takes some time to process, but even more time to wait for the children and be woken by them, and both for no good reason. The most visible effect of this change is that it avoids one taskq wakeup per ZIL block written, previously used to run zio_ready() for lwb_root_zio and skipped now. Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Motin <mav@FreeBSD.org> Sponsored by: iXsystems, Inc. Closes openzfs#15398
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.
zio_root() has no arguments for ready callback or parent ZIO. Except one recent case in ZIL code if root ZIOs ever have a parent it is also a root ZIO. It means we do not need READY pipeline stage for them, which takes some time to process, but even more time to wait for the children and be woken by them, and both for no good reason.
The most visible effect of this change is that it avoids one taskq wakeup per ZIL block written, previously used to run zio_ready() for lwb_root_zio and skipped now.
Before #15122 logical ZIOs were not waiting for READY of other logical ZIOs, so the issue was some smaller, but there were issues with missing dependencies. This PR formalizes the behavior, trying to get best from both sides.
Types of changes
Checklist:
Signed-off-by.