Cache line contention prevents scaling of 100Gbps performance
Bug #1832909 reported by
dann frazier
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Committed
|
Undecided
|
dann frazier | ||
Disco |
Fix Released
|
Medium
|
dann frazier | ||
Eoan |
Won't Fix
|
Undecided
|
dann frazier |
Bug Description
[Impact]
100Gbps network performance, as measured on an hns3 controller, doesn't scale as queue size goes up.
[Test Case]
Use a traffic generator instrument to generate load, using the SUT as an IP forwarder.
19.04 today:
8 queue 12 queue 16 queue 24 queue
37G 45G 38G 33G
With the patch applied:
8 queue 12 queue 16 queue 24 queue
37G 50G 47G 47G
[Fix]
14bd9a607f908 iommu/iova: Separate atomic variables to improve performance
[Regression Risk]
The patch makes no functional change, just reorders members of a structure. However, it is possible that this has unforeseen negative performance impacts on some platform.
CVE References
Changed in linux (Ubuntu Disco): | |
status: | New → In Progress |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Disco): | |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Disco): | |
status: | In Progress → Fix Committed |
Changed in linux (Ubuntu Eoan): | |
status: | In Progress → Fix Committed |
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This bug is awaiting verification that the kernel in -proposed solves the problem. Please test the kernel and update this bug with the results. If the problem is solved, change the tag 'verification- needed- disco' to 'verification- done-disco' . If the problem still exists, change the tag 'verification- needed- disco' to 'verification- failed- disco'.
If verification is not done by 5 working days from today, this fix will be dropped from the source code, and this bug will be closed.
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