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Merged
merged 1 commit into from
Feb 6, 2025
Merged

Add kstats tracking gang allocations #17003

merged 1 commit into from
Feb 6, 2025

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pcd1193182
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Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.

Motivation and Context

Gang blocks have a significant impact on the long and short term performance of a zpool, but there is not a lot of observability into whether they're being used.

Description

This change adds gang-specific kstats to ZFS, to better allow users to see whether ganging is happening. There are only two kstats in this version; number of gang fallbacks, and number of multi-level gang fallbacks. If people have suggestions for other stats, they can be added.

How Has This Been Tested?

Forced ganging on for small block sizes, checked that stats increased appropriately.

Types of changes

  • Bug fix (non-breaking change which fixes an issue)
  • New feature (non-breaking change which adds functionality)
  • Performance enhancement (non-breaking change which improves efficiency)
  • Code cleanup (non-breaking change which makes code smaller or more readable)
  • Breaking change (fix or feature that would cause existing functionality to change)
  • Library ABI change (libzfs, libzfs_core, libnvpair, libuutil and libzfsbootenv)
  • Documentation (a change to man pages or other documentation)

Checklist:

amotin
amotin reviewed Jan 28, 2025
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amotin
amotin reviewed Jan 29, 2025
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@amotin amotin left a comment •
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Few thoughts to think:

  • Names like ziostat.normal_fallbacks are not exactly hint that it is about allocation.
  • We also have another allocation path for ZIL.
  • And I see we have a few more allocation-related counters inside metaslab.
  • There are some style errors.

@amotin amotin added the Status: Code Review Needed Ready for review and testing label Jan 29, 2025
@pcd1193182 pcd1193182 force-pushed the gang_kstats branch 2 times, most recently from e7a07af to 0477f3d Compare February 4, 2025 21:06
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amotin commented Feb 5, 2025

@pcd1193182 "error: commit message body contains line over 72 characters"

Add kstats tracking gang allocations
7e3caa6 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Signed-off-by: Paul Dagnelie <[email protected]>
@amotin amotin added Status: Accepted Ready to integrate (reviewed, tested) and removed Status: Code Review Needed Ready for review and testing labels Feb 6, 2025
@amotin amotin merged commit 88020b9 into openzfs:master Feb 6, 2025
24 of 25 checks passed
ixhamza pushed a commit to truenas/zfs that referenced this pull request Feb 25, 2025
@pcd1193182 @ixhamza
Add kstats tracking gang allocations
cbcdc52 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes openzfs#17003
ixhamza pushed a commit to ixhamza/zfs that referenced this pull request Feb 27, 2025
@pcd1193182 @ixhamza
Add kstats tracking gang allocations
a0f8d3c 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes openzfs#17003
pcd1193182 added a commit to KlaraSystems/zfs that referenced this pull request Mar 24, 2025
@pcd1193182
Add kstats tracking gang allocations
f812219 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes openzfs#17003
lundman pushed a commit to openzfsonosx/openzfs-fork that referenced this pull request Jun 2, 2025
@pcd1193182 @lundman
Add kstats tracking gang allocations
327a383 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes openzfs#17003
lundman pushed a commit to openzfsonosx/openzfs-fork that referenced this pull request Jun 2, 2025
@pcd1193182 @lundman
Add kstats tracking gang allocations
c5efa7c 
Gang blocks have a significant impact on the long and short term
performance of a zpool, but there is not a lot of observability into
whether they're being used.  This change adds gang-specific kstats to
ZFS, to better allow users to see whether ganging is happening.

Sponsored-by: Klara, Inc.
Sponsored-by: Wasabi Technology, Inc.
Reviewed-by: Alexander Motin <[email protected]>
Reviewed-by: Tony Hutter <[email protected]>
Signed-off-by: Paul Dagnelie <[email protected]>
Closes openzfs#17003
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@amotin amotin amotin approved these changes

@tonyhutter tonyhutter tonyhutter approved these changes

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