LabVIEW
LabVIEW 2009 slow performance
A simplified project looks like this:
In other projects there is more than one shared variable (a very large string). The DLL is a simple linear search device used to pluck out variable values tied to measurement names in the for <Value Name>;<Floating Point As Double><CR NL>.
Memory use is not that extreme. Much busier projects of the same type seem to use a grand total of 55 MB as a binary. This is consistent with useage I've seen with Windows XP. Most of that is the Libraries and LabVIEW loading as a sort of virtual machine. The OS can not really separate the two consistently likely due to the dependency of binaries to load a whole lot of the guts of LabVIEW to run at all. In cases where there is more than one network variable I concatinate them together before tying them into the DLL due to the need to only have a single copy of the DLL during operation. I've seen more than one copy of a DLL opened by a VI cause unstable operation in the past.
Bob
I'm going to apologize in advance for not being horribly familiar with your application, but are you dealing with an external data source that is returning a very large string? (I guess I'm wondering why we are just using one huge variable to hold multiple values)
I'm not quite clear as to where you're seeing the slowdowns at run-time, either. Is it a cumulative process, or all at one point in the startup process?
One thing you can try to isolate the problem: replace the DLL with an equivalent LabVIEW function and see how it affects performance.
Here is the edited and working version (very close) to what Caleb wrote:
The C# DLL uses the String.Split() function to do pretty much the same thing:
using System;
using System.Collections.Generic;
using System.Text;
namespace StringToVars
{
public class StringToVars
{
String InString;
int Count;
public StringToVars()
{
InString = "";
}
public void Update(String vars)
{
InString = vars;
}
public Double GetValue(String var)
{
String[] temp;
Double Value;
String[] List = InString.Split('\n');
foreach (String s in List)
{
if (s.Contains(var))
{
temp = s.Split(';');
Value = System.Convert.ToDouble(temp[1]);
return Value;
}
}
return 0.0;
}
public int VarsCount()
{
String[] temp = InString.Split('\n');
Count = temp.Length;
return Count;
}
public String All()
{
return InString;
}
}
}
Bob
