QtQuick 2 animation performance issue

[dvolosnykh]

Consider example below:

@
import QtQuick 2.0

PathView {
width: 1280
height: 720
cacheItemCount: 7
pathItemCount: 7
preferredHighlightBegin: 0.5
preferredHighlightEnd: 0.5
model: ListModel {
ListElement {
color: "orange"
text: "first"
}
ListElement {
color: "lightgreen"
text: "second"
}
ListElement {
color: "orchid"
text: "third"
}
ListElement {
color: "tomato"
text: "fourth"
}
ListElement {
color: "skyblue"
text: "fifth"
}
ListElement {
color: "hotpink"
text: "sixth"
}
ListElement {
color: "darkseagreen"
text: "seventh"
}
ListElement {
color: "salmon"
text: "eightth"
}
ListElement {
color: "darkolivegreen"
text: "nineth"
}
ListElement {
color: "navy"
text: "tenth"
}
}
delegate: Item {
width: 150
height: 150

    Rectangle {
        id: rect
        anchors.fill: parent
        color: model.color
        opacity: 0.8
    }

    Text {
        anchors.centerIn: parent
        text: model.text
        color: "white"
        font.pixelSize: 24
    }
}
path: Path {
    startX: -150
    startY: height / 2
    PathLine {
        x: width + 150
        relativeY: 0
    }
}

NumberAnimation on offset {
    from: 0
    to: count
    loops: Animation.Infinite
    duration: 4000
    Component.onCompleted: start()
}

}
@

The animation is jerky for Qt versions 5.1.1 and 5.3.2 (Ubuntu 14.04), and 5.2.1 (embedded Linux). I guess, this is the garbage collector affecting performance, but since UI structure does not change such suggestion might be irrelevant. Is there anything can be done to make animation run smoothly?

[Gianluca]

Strange usage of "offset" property. From what I know should be used only for setting the initial configuration of the PathView.
Try to animate the currentIndex property.

[dvolosnykh]

Interesting, I don't experience this issue on Mac OS X 10.10.

[Torgeir]

This seems smooth to my eyes in both Windows 7 and Kubuntu 14.10.

Is the jerkyness very subtle? If not, can you check if any processes are possibly loading your CPU? Is vsync enabled or disabled?

Anyway I really do not think QML garbage collection plays any part in this performance.

[dvolosnykh]

I've checked that on Windows 7 and its rather smooth, too, even that it runs on 10 years old laptop.

Jerkyness is easily noticeable and reproduces constantly and consistently: extremely jerky at the very start of the application and then it becomes acceptably smooth with periodical (approximately over a constant time period) freezes for a short time.

Veryfied issue on Ubuntu 12.04 laptop. Sync to VBlank is enabled in NVIDIA X Server Settings.

[dvolosnykh]

I've updated my video graphics adapter driver to the most recent version, and now animation is rather smooth, except for some flickering.