X apps are laggy under Xmir

Bug #1502738 reported by Daniel van Vugt on 2015-10-05
This bug affects 1 person
Affects Status Importance Assigned to Milestone
xorg-server (Ubuntu)

Bug Description

X apps are very laggy under Xmir.

This is a simple problem whereby Xmir has introduced a second layer of nesting on top of an already laggy nested system.

I have a solution for this bug ready, but it can't be enabled until Unity8 bug 1497828 is fixed.

Changed in xorg-server (Ubuntu):
importance: Undecided → Medium
Daniel van Vugt (vanvugt) wrote :

Still blocked by QtMir bug 1497828? Need to retest...

Daniel van Vugt (vanvugt) wrote :
Changed in xorg-server (Ubuntu):
status: In Progress → Fix Committed
Launchpad Janitor (janitor) wrote :

This bug was fixed in the package xorg-server - 2:1.17.3-2ubuntu3

xorg-server (2:1.17.3-2ubuntu3) xenial; urgency=medium

  * debian/patches/xmir.patch:
    - Add ability to set title for XMir (LP: #1542028)
    - Use swapinterval 0 (LP: #1502738)
    - Add sufficient traversal hacks for Matchbox

 -- Robert Ancell <email address hidden> Mon, 15 Feb 2016 17:32:21 -0800

Changed in xorg-server (Ubuntu):
status: Fix Committed → Fix Released
Daniel van Vugt (vanvugt) wrote :

Un-fixed on trunk. I'm finding particularly under Unity8 the reduction is smoothness is annoying. Even though there is a reduction in lag.

Possibly the frame scheduling logic needs to be reassessed with interval zero in mind. Also a working GLX swap interval implementation would help GLX apps.

Changed in xorg-server (Ubuntu):
status: Fix Released → Triaged
Daniel van Vugt (vanvugt) wrote :

In case anyone is wondering, the two bugs that were blocking this feature remain fixed. It's not like I didn't verify them thoroughly. Just that it now looks like there are approximately two more new previously unforeseen bugs that are getting in the way.

Daniel van Vugt (vanvugt) wrote :

Now bug 1546401 is blocking this. And I think possibly another one...

summary: - X apps are very laggy under Xmir
+ X apps are laggy under Xmir
Daniel van Vugt (vanvugt) wrote :

Bug 1546401 is indeed not a bug, but is also still true. Setting swap interval 0 on the server without any replacement throttling will hurt client performance.

Daniel van Vugt (vanvugt) wrote :

I think this should mostly be fixed now in Mir 0.26 due to client-side vsync. However as previously mentioned, more work is required specifically to make the Xmir case optimal:

Changed in xorg-server (Ubuntu):
status: Triaged → Incomplete
assignee: Daniel van Vugt (vanvugt) → nobody
Launchpad Janitor (janitor) wrote :

[Expired for xorg-server (Ubuntu) because there has been no activity for 60 days.]

Changed in xorg-server (Ubuntu):
status: Incomplete → Expired
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