CPU load on asynchronous operations

[F. Walker]

I've some curious effect:
Every time I use a kind of asynchronous operation like
AnalogMultiChannelReader.BeginReadMultiSample and call this function again
in the callback-routine I've got a CPU-load of 50-60% (it's an 2,8GHz CPU).
IMO this is a little too much. Is this a konwn bug and is there any solution
for this problem?

thanks

Exaple code:
(the timing-parameters and the number of samples have no crucial effect)

//at task config
Task AITask = new Task("AITask");
AITask.AIChannels.CreateVoltageChannel("Dev1/ai0","",AITerminalConfiguration
..Differential,-10,10,AIVoltageUnits.Volts);

AITask.Timing.ConfigureSampleClock("",
1000,
SampleClockActiveEdge.Rising,
SampleQuantityMode.ContinuousSamples);

AnalogMultiChannelReader.anal
ogInReader= new
AnalogMultiChannelReader(AITask.Stream);
analogCallback = new AsyncCallback(AnalogInCallback);
analogInReader.BeginReadMultiSample(1000,analogCallback, null);

//at AnalogInCallback(IAsyncResult ar)
data = analogInReader.EndReadMultiSample(ar);
//make something with data...
analogInReader.BeginReadMultiSample(this.pointsToRead,analogCallback, null);

[bilalD]

Hello

This is not really a problem. Check out this KB. Basically, the CPU yeilds to any process that needs to use the CPU, so it should not affect the other processes.

Bilal Durrani
NI

[F. Walker]

The problem is: it has effect to my application....
exp:
I acquire 5000 samples with an (max) AI convert rate of 100000 saples/sec by
using the AnalogMultiReader.BeginReadSample - method called in an loop at a
separat thread.
So i start the thread and additionally call every 10ms the
AnalogMultiReader.ReadSingleSample -function of the same ni-ai-task in my
applikation. in this situation i got problems with starting an ni-analog
output task, the command executed with a time delay of ca. 5-10sec.
But I've found a solution for the problem by using the WaitUntilDone(0)
method of the ai-task. so the cpu usage is cut to the half and the execution
of the ao-task is done immediately.
even so thanks for the answer!
f. walker

"bilalD" schrieb im Newsb
eitrag
news:50650000000500000091510100-1073519706000@exchange.ni.com...
> Hello
>
> This is not really a problem. Check out this
>
href="http://digital.ni.com/public.nsf/websearch/09D80223FA84113D86256D6A004
B97C3?OpenDocument">KB.
> Basically, the CPU yeilds to any process that needs to use the CPU, so
> it should not affect the other processes.
>
> Bilal Durrani
> NI