Mir

Multi-monitor: clone mode much slower (stutters) than sidebyside

Bug #1213801 reported by Daniel van Vugt
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Mir
Fix Released
Medium
Daniel van Vugt
mir (Ubuntu)
Fix Released
Medium
Unassigned

Bug Description

I just noticed a strange performance penalty of clone mode. If running several clients, in clone mode some of them (notably demo_client_accelerated) will stutter. However using the same two monitors sidebyside everything is perfectly smooth. Therefore, the hardware can clearly keep up with multi-monitor and it's only an issue in clone mode.

This is probably a symptom of clone mode forcing each page flip to wait for multiple vblanks...

And yes, I have tested with and without the "switch" branch. The bug existed before that landed.

Tags: multimonitor

Related branches

Revision history for this message
Daniel van Vugt (vanvugt) wrote :

On the other hand, waiting for all outputs' page flips to complete does avoid tearing. And this bug doesn't occur until the rendering load is high.

I think we need to choose between:
  (a) Sometimes low frame rate (stutter) but never tearing; or
  (b) Always smooth frame rate but tearing on /some/ monitors in clone mode.

I'm really hoping there's an option (c).

Changed in mir:
importance: Undecided → High
status: New → Triaged
Changed in mir:
assignee: nobody → Daniel van Vugt (vanvugt)
status: Triaged → In Progress
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

Found option (c)

Changed in mir:
milestone: none → 0.1.5
Changed in mir:
milestone: 0.1.5 → 0.1.6
Revision history for this message
PS Jenkins bot (ps-jenkins) wrote :

Fix committed into lp:mir/devel at revision None, scheduled for release in mir, milestone Unknown

Changed in mir:
status: In Progress → Fix Committed
Changed in mir:
importance: High → Medium
Changed in mir:
status: Fix Committed → Fix Released
Revision history for this message
Daniel van Vugt (vanvugt) wrote :

This bug was fixed in the package mir - 0.1.6+14.04.20140310-0ubuntu1
---------------
mir (0.1.6+14.04.20140310-0ubuntu1) trusty; urgency=medium

Changed in mir (Ubuntu):
importance: Undecided → Medium
status: New → Fix Released
To post a comment you must log in.
This report contains Public information  
Everyone can see this information.

Other bug subscribers

Remote bug watches

Bug watches keep track of this bug in other bug trackers.