mlx4_en didn't choose time-stamping shift value according to HW frequency
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
linux (Ubuntu) |
Fix Released
|
Medium
|
Tim Gardner | ||
Xenial |
Fix Released
|
Medium
|
Tim Gardner |
Bug Description
Hi,
Previously, the shift value used for time-stamping was constant and didn't
depend on the HW chip frequency. Change that to take the frequency into account
and calculate the maximal value in cycles per wraparound of ten seconds. This
time slot was chosen since it gives a good accuracy in time synchronization.
Algorithm for shift value calculation:
* Round up the maximal value in cycles to nearest power of two
* Calculate maximal multiplier by division of all 64 bits set
to above result
* Then, invert the function clocksource_
maximal mult value
below is the upstream commit that should fix the issue
commit 31c128b66e5b28f
Related branches
Changed in linux (Ubuntu): | |
status: | Incomplete → Confirmed |
importance: | Undecided → Medium |
Changed in linux (Ubuntu Xenial): | |
assignee: | nobody → Tim Gardner (timg-tpi) |
status: | Confirmed → Fix Committed |
This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:
apport-collect 1552627
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.