Bug 24913 – [Qt] NPAPI: Excessive timer usage and high CPU load

• Component: Plug-ins
• Status: RESOLVED INVALID

[Firuz Kosimov]

I use qtwebkit 4.5 on my application and qtwebkit 4.5 supports flash plugin. When I enable flash plugin and navigate to a web-page with flash (youtube.com or any other with flash banner) the cpu load jumps up to 40-70% and the process-detail column "page fault delta" goes 30,000-60,000 every second. The demo-browser that is shipped with qt 4.5 has the same problem.

The steps to reproduce: 
1)install qt 4.5
2)launch demo-browser from examples (notice cpu-load doesnt stay steadily when you navigate to pages without flash)
3)navigate to youtube.com
4)The cpu usage jumps to 40-70% and it doesnt go down. "page fault delta" in the process-detail column of task manager goes to 30,000-60,000 and stays at such pace.

I guess the cpu load and "page fault delta" should not stay up that high during viewing web-pages with flash elements.

[David T. L. Wong]

I experience this problem too. 
Using Qt 4.6 and MSVC2008 on Windows XP.
Webkit source is svn trunk r53272.

It seems there are too many timer event.

I modified SharedTimerQt::start() in WebCore/platform/qt/SharedTimerQt.cpp to:

void SharedTimerQt::start(double fireTime)
{
    static int zero_interval_count = 0;
    double interval = fireTime - currentTime();
    unsigned int intervalInMS;
	if (interval < 0) {
        intervalInMS = 0;
	} else {
        interval *= 1000;
        intervalInMS = (unsigned int)interval;
    }

	if (intervalInMS == 0) {
		zero_interval_count++;
		if ((zero_interval_count % 10000) == 0) {
			printf("zero_interval_count = %d, time = %f\n", zero_interval_count, currentTime());
		}
	}
    m_timer.start(intervalInMS, this);
}

on simple flash that only display a digital clock,
It records 10,000 m_timer.start() calls, with interval equals zero, in 0.536 second

on http://www.adobe.com/flashplatform/ ,
It records 10,000 m_timer.start() calls, with interval equals zero, in 3.165 second

[Ismail Donmez]

I also see this but without any plugin, one such a page is http://en.m.wikipedia.org/wiki?search=dinasour

[Benjamin Poulain]

*** Bug 35777 has been marked as a duplicate of this bug. ***

[Jocelyn Turcotte]

=== Bulk closing of Qt bugs ===

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