Hi,
I evaluate some graphing SDKs and NI MS is one of them. The test case is the following:
Update rate: 4Hz
Number of Points on each update:5
Number of Points/Plot: 144000
Number of Plots:10
After one hour, the WaveformGraph uses 100% CPU on my PC (Core Duo 1,8GHz). Is this kind of a "expected behaviour" because the test case is too challenging?
I have to ideas how to tackle the high cpu load:
1. Use a smaller data type for plot data. Currently, I use doubles but floats would be sufficient. I thought about using
PlotWaveformsAppendMultiple instead of
PlotYAppendMultiple and using float as <TData>, but I read in the forums that MS is using doubles internally anyway, so that it would bring no performance gain. The statement is from 2006. Is this still true?
2. Only draw every 100th sample or so. Another guy who had similar problems did this here. A NI guy also said in this thread that "The problem has been fixed and will be available in the release of Measurement Studio after 8.1.". So I wonder whether this kind of interleaved sample painting is allready implemented?
Any other hints how I could speed things up are highly appreciated.
One last thing Id like to know: How can I measure the time the control needs to redraw itself? I made a wild guess and assumed that the "Invalidate" event is fired just before the controls is drawn and "Paint" is fired directly afterwards. The code I use for measurement looks like this:
private void onInvalidate(object sender, InvalidateEventArgs args )
{
stopWatch2.Reset();
stopWatch2.Start();
}
private void onPaint(object sender, PaintEventArgs args )
{
this.drawtime = stopWatch2.Elapsed;
stopWatch2.Stop();
}
Is this reasonable?
Regards,
Janosch
