Why does DAQ cause full CPU usage?

i have set up my vi to acquire a buffer of 360 data points, it acquires one point every time there is a pulse on an external channel. however whilst it is waiting for all the points it uses 100% cpu. can i stop it doing this?
Attachments:
set_up_acquire.vi ‏95 KB

Hello,
The short answer is yes. You can keep it from using 100% CPU while waiting for points. I took a look at your code. One approach would be to put AI Read.vi in a loop, read a portion of your data at a time, then accumulate all the data at the end. A way to accomplish this would be to set "number of scans to read" input of AI Read.vi to zero, watch the "scan backlog" output, then do an actual read when the backlog has the number of scans you want. This allows the program to sleep between reads. Be sure to put a small wait in the read loop.
Another approach is to use DAQ Occurrences. In this case your program sleeps at the driver level. You can find an example of this by searching on "occurrences" in the NI Example Finder.
Best Regards,
Dou
g Norman

Similar Messages

Why Xcode 4 causes 100% cpu usage?

Dear all,
I have been annoyed by the high cpu usage of Xcode 4.0.2 when editing code. It is burning my MacBook! I think this may be related to the dynamic code checking. Any idea?
Cheers,
Li

dynamic checking?
Do you mean Instruments...?
AFAIK, it's always hungry, hungry hippo - the best defense right now is to use Xcode 3.2.6.
Xcode 4 isn't 'required' just yet, but it might happen later in the year with the next OS, which may help tame it a bit.

Websites with flash content are causing tremendous CPU usage!!

Greetings!
I finally installed the long-awaited version 4 of firefox, and I am really disappointed. In addition to slight sluggishness now and again, it turns out that websites with Flash content (even those sites with a little flash advertising banner) are causing my CPU usage to really go up.
It's slowing down my machine, making my CPU fans spin loudly, and making for a disappointing web browsing experience.
I have disabled all add-ons, and done the usual. Even tried installing Chrome for the first time ever!
The problem is definitely Flash + Firefox 4.
I have created a brand new profile, but no dice. Wondering if anyone else experiences a high CPU load on pages with flash...

Adobe Flash Player has also been crashing periodically on 2 of my computers, I'm still running XP, one of them a powerful HTPC, Dell Optiplex 755 SFF over a new Cable Internet Connection. Buffering, Lagging, crashing when streaming video for Catchup TV (Freeview) via Firefox Adobe Flash Player Add-On, does not happen on Youtube though. Lagging & Crashing does NOT occur AT ALL in Google Chrome, but I hate that browser.
Have tried the usual disabling Flash Hardware Acceleration + Protected Mode, setting storage to Unlimited, disabling FF Ad Blockers + Hardware Acceleration, cleaning Caches, updating program versions, everything bar reinstalling programs. It's not happening in Chrome, why in Firefox?

Adobe stuffs cause high CPU usage

I just download Creative Cloud a few days ago for Primiere CC and since then there is always something from it that causes ~50% CPU usage. I tried to end the process by Task Manager and something else just replace the previous one's place. Sometimes it's CEP Service Manager, sometimes it's Core Sync, CEF Helper, etc. and it's driving me nut! I mean like right now Firefox only takes about 20% while those things just sky rocket the CPU usage. What should I do? How do I stop this?

Since I installed CC, my laptop has been running very hot too.

Why does firefox cause windows vista to crash

why does firefox cause windows vistra to crash

hello, as long as the download-process isn't finished a file gets the .part extension appended - this is the expected behaviour in firefox...

What does the 'rtcli async executor process' process do on a Cisco ASA and why would it cause high CPU load?

I noticed that the CPU on our ASA had jumped from around %4 to 30% consistently a few weeks back. The process below seems to be causing the load, but I can't find any information on what it does and how to resolve the issue.
ASA# sh proc cpu-usage sorted non-zero
PC Thread 5Sec 1Min 5Min Process
0x08a24505 0x1bdb0124 25.4% 25.6% 25.6% rtcli async executor process
0x081ecc51 0x1bdc0f3c 4.7% 4.3% 4.1% Dispatch Unit
0x08e4687c 0x1bdc0528 0.3% 0.3% 0.3% ssm4ge_cfg_poll_thread
0x08a496d0 0x1bdbecf8 0.1% 0.1% 0.1% Unicorn Admin Handler
0x0866d56e 0x1bdafd1c 0.1% 0.1% 0.1% ARP Thread
A little more background that has me concerned is that I have the exact time when the jump occurred. Since that time, I've lost ssh access to the ASA and can only access it via Telnet internally or the ASDM. I checked the certificates and a new one was generated exactly when the spike occurred. I am unsure wether or not that was a system triggered certificate generation, or if I have a security issue I need to address. Heartbleed maybe??
Any insight would be greatly appreciated.

Disclaimer
The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.
Liability Disclaimer
In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.
Posting
Sorry I wasn't clear, but when I was asking about "not a lot of traffic", I was wondering about actual volume passing through the 2811.
When I asked about "kind of tunnels", I was wondering about how they are configured. E.g. GRE or IPSec/GRE or VTI, encryption options, other tunnel interface options.
Perhaps the easiest way to check for fragmentation, is packet analyze the traffic passing through the 2811.

Spreadsheet functions causing 100% CPU usage

Running ColdFusion Enterprise 9,0,0,251028 with JVM 1.6.0_14 on a Windows 2003 server. I am finding that when using <cfspreadsheet> and the spreadsheet functions to build a spreadsheet the server CPU maxes out at 100% while the spreadsheet object is being built. The spreadsheet is not overly large or complex: 10-15 columns and 400-500 rows. This behavior is consistent - it happens every time, even when building a simple spreadsheet with 1 column and a few rows. Is anyone else experiencing this? Is it a known problem with a fix? Thank you.
Michael Mongeau
Stratus Technologies

I was able to root cause the excessive CPU usage to a single-CPU virtual machine. When I ran the same code on dual-CPU virtual machines the CPU usage went to 50-60% but never reached 100% and stayed there as it does on the single-CPU virtual machine. So there appears to be an issue with JRun and Apache POI on single-CPU machines. I simply had my system administrator add another CPU to the virtual machine and the problem no longer occurs.

Applet causes high CPU usage

Hallo,
I have a strange problem with my applet. It displays medical images. After loading Image the CPU usage of java jiumps to 100% on single core processors and to 50% on 2 core processors, and stays high, without any interaction of user. I've used Java VisualVM to profile the applet and it says that: javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run() 94.76343 787851 ms (94,8%) 58823 times invoked is
I'm not sure this is the cause of the problem. I don't use any loops while noone is interacting with the applet. Has anyone idea or suggestion what's going wrong?
This CPU load is independent of browser and operating system. I've profiled it on firefox.
with regards
Rafal Ziolkowski

Good job figuring it out.
Rule of thumb to prevent future problems: the paintComponent is used for painting and should do nothing else - setBorder() is a state change and thus does not belong in the paintComponent() method. You can all relate it back to a general programming rule of thumb: a function or method should perform only one task.

Recently FireFox often has been causing 100% CPU usage and locks up until it finishes the process (various ones). Clearing cookies/cache didn't help. Any ideas?

Windows 2000 SP4, 1g RAM, Firefox 9.0.1
We keep IE6 and Firefox open simultaneously for 2 different mail accounts. Firefox was always much faster even with 3 or 4 tabs open, but for the past couple of weeks when trying to update a screen the CPU suddenly goes to 100% usage and of course nothing will move until the particular process is finished. Closing one or more tabs does not help. If I close Firefox completely with Task Manager CPU usage goes back down to nil. After restarting Firefox CPU usage may or may not go back up depending upon whether it tries to continue the previous task that was locking it up.
It did not do this with Firefox 3.6 but then again it didn't happen immediately after updating to 9.0.1 either.

100% CPU usage occurred most often toward the end of the working day when busy trying to print on-line postage. We don't have any memory-consuming plugins but according to the knowledge base articles Firefox memory usage can gradually increase during the day even if you do nothing. It seems that may be the problem so we close and restart Firefox more often now as that usually fixes the problem. However, if we get stuck on a particular website update that causes the CPU to to go 100%, we can always start Firefox without previous tabs so the update will stop, or simply use a different browser until we have time to let the computer play games with itself.
So our workaround of restarting Firefox turns out to be the final solution (until we find something better - will post it if we do). Vic

Why Does kernel_task use 80 % cpu?

Hi,
Ive been having a problem with my 2ghz macbook running slowly. The first thing i did when i noticed the slowdown was to open Activity Monitor to find out what process was causing the slowdown. kernel_task was running at 84% of the cpu and had 54 threads running. I restarted the computer and PID 0 kernal_task was still running between 70 and 90% cpu.
Things i tried to fix the problem
1 uninstall all programs and games
2 remove everything connected to the computer
3 boot to os disk and repair permissions ( on boot volume and disk itself )
4 reinstall os and download updates
5 reinstall os and don't download updates
6 reinstall os and choose "erase and install" option
7 boot to os disk and use disk utility to erase disk then reinstall os
8 boot to os disk and use diskutil from terminal to repartition and reformat, then reinstall os
9 reset NVRAM/ PRAM
after this i took it to the apple store. they put a new hard drive in it (probably cause i wore out the old one reformatting it) and the problem still exists.
most of the forums say that the problem is either overheating, or a kernel extension misbehaving. both of these explanations could be the problem.
Overheating-
many macbook air users report high kernel_task cpu usage related to high cpu temps, broken fans and broken logic-boards. this is further supported buy how the problem goes away when the ambient temperature is below 60 but comes back at room temp. could this be a hardware ploblem like a bad fan, bad temp sensor or heatsink that got popped off?
CoolBook
coolbook should help solve the temp problem buy lowering the voltage to the cpu, but that sounds uber dangerous to me. plus it adds its own kext's and im trying to fix the kernel not add a bunch of 3rd party junk to it. has anybody had any luck with coolbook?
Bad kext (kernel extension)
when i boot to safe mode kernel_task behaves normaly so could the problem be a bad kext? safeboot only loads the required kernel extensions so could one of the other kexts not loaded in safe boot be the problem?
1 first question: kernel_task is a process scheduler and memory manager so is messing around with kernel extensions going to have any affect?
2 some people found that replacing the trackpad kext with an earlier version got the kernel_task to settle down has this worked for anyone?
3 i booted regularly and in safe mode and used kextfind -loaded to find out what kexts were running normally that didnt run in safe boot. I then booted to safe mode again and used kextload to load back each kext one buy one. they all loaded and kernel_task stayed the same. there was one exception GeForce.kext caused a panic and wouldnt load. is geforce.kext the problem or am i on the wrong track?
4 the way i understand it kextd is a daemon (whatever that means) that loads kernel extensions. the man pages say that the "-x" switch will make it only load the safe boot kernel extensions but kextd doesnt work from the command line because its started buy launchd (right?) is there a way to get kextd to start with the "-x" switch every time the computer boots normally?
Im a total computer noob and i welcome and any correction and advice at any level. please help me! i want to solve this whole kernel_task for everyone once and for all!
Message was edited by: Duezle
Message was edited by: Duezle

Have you counted the number of processes in AM? They are all running from time to time whether you use the computer or it sits for an hour. Not including applications you have loaded there may be upwards of 80-90 system processes running. Applications you aren't using are still partially in memory and partially being paged out to disk.
All this activity will in part use the kernel. My kernel_task process is running 1.5 GBs just now.

Why does this cause error (ORA 01008: Not all variables bound)

When I assign values to parameters for a command object, I used the following code with the .NET provider:
If oReq.CritSpec = Nothing Or oReq.CritSpec = "" Then
cmdReq.Parameters.Add(":po5", DBNull.Value)
Else
cmdReq.Parameters.Add(":po5", oReq.CritSpec)
End If
This works fine, but when I switch to using ODP it generates the 'not all variables bound' error. I checked the parameter's status and it was Success. However, if I change the second line of the statement to
If oReq.CritSpec = Nothing Or oReq.CritSpec = "" Then
cmdReq.Parameters.Add(":po5", OracleDbType.Varchar2, DBNull.Value, ParameterDirection.Input)
Else
cmdReq.Parameters.Add(":po5", nReq.CritSpec)
End If
It seems to be OK. So my question is - why does the first statement generate the error? Am I misinterpreting the overloaded constructor or it it a bug in my code? Thanks.
ck

No need to answer, I solved it.
For anyone else who might run into this, there were two issues:
1. Assigning DBNull.Value to a parameter without specifying the parameter's type causes the Value property for that parameter to not be initialized. If you reference it, it will come back as a runtime error (check it first by testing for IsNot Nothing).
2. In my update code, I have a lot of where clauses like "WHERE (COL1 = :1 OR COL1 IS NULL AND :1 IS NULL)". The default binding for parameters treats these two references to :1 as two different parameters. Setting BindByName to true solves the problem.
ck
Edited by: user536671 on Feb 15, 2009 7:04 PM

Small Acrobat file causes 100% cpu usage with v. 7.09

Using Acrobat professional 7.09
I have a small acrobat file (94k) that causes my cpu to peg at 100% I used acrobat professional to convert an eps file to a pdf file. Is there a general known issue that could be causing this?
Stephen

> Looking at the plot, you might want to consider trying to use a vector graphic in the future. It looks like a plot that you may have created in MATLAB or such. In that case, why not just print to the PDF.
I used matplotlib, which can generate png, eps, svg, or even pdf files. The pdf in question was converted by acrobat from eps, which has worked well for me in the past. I wish acrobat pro 7 could handle svg.
Stephen

Btrfs + luks cause serious CPU usage

I often tried to forget about this, but in a time I use a external disk with btrfs.
bus as soon as I mount the disk via luks mapper device, I get serious CPU usage by kthreads. It goes that far that even typing into pidgin gets lagged/delayed.
Does anybody else have this kind of issue? An internal disk has the verysame effect. Tested copies with these combinations: ext4→btrfs; btrfs→btrfs; btrfs→ext4
Thank you!
Appendix:
Phenom 9500 4x 2.2
8GB DDR2 SDRAM
so the system should be pretty much capable of anything :>
Last edited by drahnr (2011-06-29 11:01:43)

I use pretty much the same options as you:
$ grep backup /etc/fstab
/dev/mapper/backup /mnt/backup btrfs defaults,noauto 0 0
I use the standard kernel from testing which is 2.6.39 though I have not seen this behavior on any previous kernel either.
If you don't use an indexer and something like iotop shows no activity I'm not sure what to try next. If you have hourly backups in place how many snapshots are there present on the volume? Are they being rotated or just building up? Could btrfs be doing some sort of rebalance (seems unlikely on a single disk pool)? Probably not being much help sorry.

For Experts: Why does LabView cause System reboot while accessing hardware with driver?

Hello NI Developers!
I use LabView 7.1 under Windows XP
I have a programm console application which accesses through Jungo Windriver PCI-E board.
This program works fine - and performs DMA data transfer between PC and Board's memory.
In order to implement this console application work together with LabView I did following:
1) Added this function inside the source:
_declspec(dllexport) void LVMainFunction(uInt32 *IntValue);
_declspec(dllexport) void LVMainFunction(uInt32 *IntValue)
    AllocConsole();                   //Open new console window
   SetConsoleTitle(L"Debug Window"); //Set a title for console window
    freopen("CONOUT$","a+",stdout); //redirec standard output stream to current window so
                                    // so we are able to see "printf" outputs
   freopen("CONIN$","a+",stdin);    //redirec standard input stream to current window so
                                    // so we are able pass inputs from keyboard
   main();                          //Call applications main function which does all the work
2) Compiled this new source as DLL library
3) Call LVMainFunction(...) function from LabView using Call Library Node
In the result: Executing VI - opens new console window, shows debug outputs and receives keyboard inputs.
It works fine till the last function, which perform DMA data transfer - and reboots PC.
1) Why does this happen?
2) I understand that opening console from Call Library Node, attaches together this console window and running VI. So If I close one of them - both windows closes.
   So does LabView have somekind of restrictions of accessing Hardware's functions?
I can read Board's resource information and view size of memory on board, interrupt functions and other information about device, but when I try to reach
DMA my system reboots. And I understand that this should be some kind of LabView problem, cause I tried different implementations, even without use of
console window - and the result is the same.
3) Should I split the program in to two separate processes and perform data exchange using Sockets or Pipes techology?
Thank you in advance!
ACiDUser
Message Edited by ACiDuser on 11-13-2008 09:37 AM

Hello!
At LAST!!!
I solved this problem!
From the beginning I was following National Instruments manual on how to build DLL with external IDE:
http://zone.ni.com/reference/en-XX/help/371361A-01/lvhowto/building_library_project/
Set the Struct member alignment control to 1 Byte.
Now this option caused my PC to reboot!
So could someone explain why this happened? and If it is a bad tip, so it's better to remove from manual. Then other people will not have such problems as I did
- wasting 2 monthes of time determining the problem.
I changed it to Set the Struct member alignment control to DEFAULT.
and now everything works fine.
Regards
Message Edited by ACiDuser on 11-13-2008 11:14 AM

Tab selection property causing 100% CPU usage

Hi,
I've having some trouble with using property nodes to tab selection. After 1-2 hours the CPU usage is 100%. The VI is attached. I'm using LV 6.0.2 on win2000. Does anyone have a clue of what's happening?
Attachments:
tab_selector_property.vi ‏22 KB

Every time the while loop executes, you open *new* pages reference array. Whitout closing them, you quickly fill the memory and hog the computer usage. As in the modified VI attached, get the references only once outside the while loop and reuse them. Close any reference after use. As much as possible, you shoud use the control terminal to read its value instead of reading the value property.
LabVIEW, C'est LabVIEW
Attachments:
tab_selector_property.vi ‏25 KB

Why does DAQ cause full CPU usage?

Similar Messages

Maybe you are looking for