please enable CONFIG_ARM64_LSE_ATOMICS
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
dann frazier | ||
Xenial |
Won't Fix
|
Undecided
|
dann frazier | ||
Yakkety |
Won't Fix
|
Undecided
|
dann frazier | ||
Zesty |
Won't Fix
|
Undecided
|
dann frazier |
Bug Description
[Impact]
Performance is lowered for ARM >= v8.1 cpus by not taking advantage of the "Large System Extenstion" atomic instructions they provide.
Note: This config was enabled during xenial development, but was disabled to workaround a FTBFS[*] due to us not having a new enough binutils to support it. binutils was later updated in xenial, and supports these instructions.
[Test Case]
grep CONFIG_
[Regression Risk]
There is a known small performance overhead for < ARMv8.1 arm64 systems (noted in the Kconfig). To mitigate the risk of runtime or build failures, this should be tested on both ARMv8 and >= ARMv8.1 systems, to exercise both code paths.
[*] https:/
Changed in linux (Ubuntu): | |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Xenial): | |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Yakkety): | |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Zesty): | |
assignee: | nobody → dann frazier (dannf) |
description: | updated |
description: | updated |
description: | updated |
Changed in linux (Ubuntu): | |
status: | Incomplete → In Progress |
Changed in linux (Ubuntu Xenial): | |
status: | Incomplete → Confirmed |
Changed in linux (Ubuntu Yakkety): | |
status: | Incomplete → Confirmed |
Changed in linux (Ubuntu Zesty): | |
status: | Incomplete → Triaged |
Changed in linux (Ubuntu Yakkety): | |
status: | Confirmed → Triaged |
Changed in linux (Ubuntu Xenial): | |
status: | Confirmed → Triaged |
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1691614
and then change the status of the bug to 'Confirmed'.
If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.
This change has been made by an automated script, maintained by the Ubuntu Kernel Team.