hisi_sas: improve performance by optimizing DQ locking
Bug #1774472 reported by
dann frazier
This bug affects 1 person
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Undecided
|
dann frazier | ||
Bionic |
Fix Released
|
Undecided
|
dann frazier |
Bug Description
[Impact]
The way the driver deals with locking the DQ causes performance to suffer.
[Test Case]
Run iozone3 and validate performance is >= previous.
[Fix]
Once a DQ slot is allocated, it must be used. So, currently the driver locks the DQ while it builds and sends each task to the hardware, just in case there is a failure, so that it can reuse that slot. However - there is a point at which we the build/send is guaranteed to succeed, so we can release the lock at that point allowing new slots to be allocated.
[Regression Risk]
All fixes are localized to the hisi_sas drivers, which are drivers for the controllers in the hip06/hip07 SoCs, where we have directly tested these updates.
CVE References
Changed in linux (Ubuntu): | |
status: | Incomplete → In Progress |
Changed in linux (Ubuntu Bionic): | |
status: | New → In Progress |
Changed in linux (Ubuntu): | |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Bionic): | |
assignee: | nobody → dann frazier (dannf) |
Changed in linux (Ubuntu Bionic): | |
status: | In Progress → Fix Committed |
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This bug is missing log files that will aid in diagnosing the problem. While running an Ubuntu kernel (not a mainline or third-party kernel) please enter the following command in a terminal window:
apport-collect 1774472
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.