Determining system load

Is it possible for the Java RTS to return information about the load the threads it manages are putting on the CPU? I have developed a number of alternative schedulers using the priority scheduler as my base (using some of the ideas brought up on this forum and some ideas from Dr. Andy Welling's book), and I would like to test them.
Specifically, since the algorithms are really simulations of other scheduling policies using priority scheduling, I am interested in determining the execution magnitudes at which the overhead associated with the simulation becomes neglectable i.e. at what execution magnitudes do the developed schedulers begin to approach the ideal system load before missing deadlines. For example, for the EDF scheduler I am interested in knowing the thread execution magnitudes at which the system load at which a deadline is first missed is 1.

If you're running Java RTS on Solaris, DTrace is able to provide you all the details about the time each thread is running on each processor. You could also download the tool called Thread Scheduling Visualizer (TSV) on Java RTS download page. This tool is using DTrace to record this kind of information and provides a graphical view of the scheduling of the different threads. The TSV bundle also contains a directory called DTraceToolBox with several DTrace scripts. The script named thread_cpu_prio.sh should do something close to what you're looking for.
Frederic Parain

Similar Messages

No system load data available in st03

Dear Guru,
When i am executing Tcode ST03 it is showing that "No system load data available"
when i am executing "RSSTAT83" report then its thriwing "LOGDB_SSCR_NOT_FOUND" dump.
statndard job getting cancelled thats why i hae change the status of all standard btc jobs.
but system is still too much slow. Right now there is no job running.my patch level is also 14 of both abap & basis.
What to do......

Hi Gaurav
this kind of error belongs to In correct time Zones, OS Time and R/3 Time was different, please set both time zones same in all clients using STZAC Tcode
again if not slove your problem then fallow this procedure.
It is possible that the workload collector is not schedule. To schedule the collector, choose, in Expert user mode, Collector -> Perf. Monitor Collector -> Execution Times in the left subscreen. The system displays the Contents of table TCOLL screen. Ensure that the report RSSTAT83 is scheduled hourly.
if not scheduled hourly, then execute aboue report in SE38
Regards
Bandla

URLClassLoader slower than system loader

I'm subclassing URLClassLoader to load jar files on the local file system. I noticed that URLClassLoader loads about 30% slower than placing the jar files on the system class path. In my app, class loading performance in very important -even though it is just a one time hit.
I suspect the URLClassLoader (which I believe is implemented mostly in Java on Sun's VM) is not leveraging the many performance optimziations that the system loader enjoys (which is probably implemented in native code).
I also experience the same performance issue if I try to do jar loading myself using Java ZipFile i/o.
Comments?

well there is quite more overhead involved - loading from classpath of course is the most optimized one.

System.load fails in Vista

Hi All!
I am using JNI to call a DLL for my Java Application. It works fine in windows-XP, but doesn't work in Vista.
I am using following code:
System.load(absolute_path_to_DLL);
I was astonished to see that it works fine from eclipse workspace(on Vista) when i debug the code, but does not work from installed location.
I have set classpath to all the needed jars and dlls and set PATH variable also and use following code in batch file to execute the main class:
JAVAW com.pack1.pack2.mainClass
Please help me to sort out the problem. Thanks.
Regards,
Zia

"Does not work" tells us nothing.
Either it threw an exception on the load or it didn't. If it did then then print the stack trace and post.
If it didn't throw an exception then there is another problem.
Presumably you are using java 1.6.

System.load("path") problem

hi all,
I am facing a problem to load a library using System.load("abc.lib"). Its throws a unsatisfied link error. But, if i use the absolute path, then its successfully load the library.
Please help me, how can i load a libray using parameter in relative path..
Thank you

abc.lib is my current working directory and i used System.load("./abc.lib") but it raised the same problem.
I browse the API that System.load() takes the absolute path not relative path.
I am using this in an applet.
Please help me, how can i resolve this problem.
Thank you

System load application (stress measurement)

Hi,
I am about to create a Benchmark application. The main purpose of the application is to compare performance between Linux and Windows NT. Two PCs equipped with Gigabit Ethernet cards are to be connected point-to-point.
(*PC, Sender*)---->UDP/TCP channel---->(*PC, Receiver)
One PC will load the other PC by sending either TCP or UDP packets. I have already written both receiver and sender applications, but I need to monitor the system load at the receiving end. My question is whether it is possible to perform the following actions with Java code.
* Measure the CPU usage on the receiving PC.
* Monitor the level of PCI bus traffic.
* I want to monitor the memory load. (more precise than freeMemory() and totalMemory() )
If any of these options are possible, where can I find more info/sample code ? I have heard something about JNI, but I don't really know what that is.

The comparison would be unfair (by your definition of unfair) in Java, too, since the JVMs for both platforms are different.
If you are dealing with time, though, 500 milliseconds is 500 milliseconds, no matter what language you write it on or what platform you run it on. If you use VC++ for the Windows stuff, make sure you disable Microsoft extensions so you have some ANSI standard code that will compile with gcc.
Since you are trying to compare operating systems, make sure both machines are using the same processors (and motherboards with the same PCI bus architecture), too. And have the same amount of memory, which is the same speed and architecture on both. Their hard drives should be roughly the same speed, too. The PCI bus usage could vary with network cards, so having the same network cards will be a plus. What it seems to come down to is that you are going to end up measuring the performance of the socket library implementations on both machines.
As far as JNI goes, all it is is a way to write native code and use it in your Java application. I don't know much about it, search around for some examples. There's a tutorial, somewhere, too. Some dude on here, tpritchet, seems to know a lot about it.
Jason

GPU Acceleration in Chromium causes heavy system load

I experience a heavy system load (especially if I'm watching videos or listening to music on soundcloud) if I use the hardware acceleration feature in Chromium.
I use the standard linux kernel(not the lts one) and the drivers from the nvidia-package. I got a Nvidia GeForce GT 525M GPU.
If I deactivate the hardware acceleration feature in chromium, it doesn't need so much system resources, but maybe there are more factors which cause the heavy system load.
I'd like to be able to activate the feature, because otherwise I can't scroll through webpages smoothly.
The same thing happens if I use the google-chrome package from the AUR.
Has somebody experienced the same problem and/or has ideas how to solve it?

Isn't HW acceleration disabled by default on Linux? AFAIR it always had a lot of problems.
Last edited by dwe11er (2014-10-22 13:32:17)

Jni library loaded by System.load fails on later call to System.loadLibrary

I'm attempting to use jnotify to listen for directory modifications. This requires using jni to dynamically link to a c library. I have gotten everything to work successfully if I put the library on the java.library.path. However, I would prefer to let my application specify the full path to the jnotify library. My understanding is that I should be able to do a System.load("/foo/libjnotify.so") in a static block and then subsequent calls to System.loadLibrary("jnotify") should do nothing as the library is already loaded. However I am getting a 'Exception in thread "main" java.lang.UnsatisfiedLinkError: no jnotify in java.library.path'. Am I misunderstanding the correct usage of these System calls?

Joe wrote:
That makes sense.
The System.loadLibrary portion is in a 3rd party library which I am legally not allowed to change.
Are there any other possible ways to accomplish the loading without the library being on the java.library.path?
You have two problems - not one.
The library itself is calling loadLibrary(). The standard idiom is that one does that in a static block. If a static block throws an exception, any exception, then the class will not load.
Presumably the library is not checking for a duplicate library load. So your problem is that that loadLibrary() call must not throw an exception.
Thus you cannot preload the library.
Far as I can see you have the following options.
- Put it on the path.
- Create a jave exec handler (via Runtime.exec or jni), put the library on that path before you start another VM which does the real work.
- Modify the java API loadLibrary() call so it catches the dup exception, that of course requires a boot option.

System load monitoring

Hi, please advise.
I have two business processes, one old process and another new - optimized process. Question is how to measure the system load (total) for realization of the first - old process and new process to measure difference of how the processes load the system.
I need to measure the system load only for realization of the processes (each process consists of several transactions).
I want to measure the load for realisation of the first process and know how it loads the system and then make the same measurement for the second process - so two separate measures are needed.
I work in SAP R/3 Enterprise.
Thank you for any advice.
Lubos

Hi,
i have tried tx SAT - but it is not available for me, so i make measurements thorugh se30. There is no problem with transactions like FB60, FF67 etc. but when I try to measure the F110 transaction system shows an error during the measurement. Message number: S7068, diagnosis: see note 170470.
Do you know what problem could it be.
I´m a newbee in this.
Thank you for any replies.

System.load(PATH_TO_LIB) issue inside java package

Hi all,
sorry if this has been asked somewhere, but I just could not find any answer of it. I simply want to load a library by using System.load(ABSOLUTE_PATH_TO_LIB) and call its native function. I could get this to work if I call this function in a class without having any package to it.
However, when I moved the class into a package, e.g. com.test package, I will get java.lang.UnsatisfiedLinkError exception. I am certain the System.load could still reference to the lib I pointed to, just that the library is not really loaded and resulting in this error when I call the native method. Any help would be greatly appreciated, thanks in advance.
Sudi

Hi, thanks for the reply.
I have found the problem, the problem was not in the System.load, as I mentioned earlier, I can load the library, but I got unsatisfied link error when I call the native function inside a java package.
The reason to this is the C native function actually does not allow me to call the function from a java package. If I want to call it from a package, then I have to regenerate the header file and the C source code, namely every functions gonna have the package name follow, e.g. au_com_siab_java_helloworld. something similiar to that. Too bad, this is an existing library that I am trying to use and I don't have the source code to change. Thanks all.

When i open EMC on 2010 cas server i get "the system load quota of 1000 requests per 2 seconds has been exceeded"

when i open EMC on 2010 cas server i get "the system load quota of 1000 requests per 2 seconds has been exceeded"
and it wont load

when i open EMC on 2010 cas server i get "the system load quota of 1000 requests per 2 seconds has been exceeded"
and it wont load
Close EMC and Powershell and run iisreset.
Twitter!: Please Note: My Posts are provided “AS IS” without warranty of any kind, either expressed or implied.

ST03 No System Load data available

Hi Experts,
       When am trying to execute ST03, it displaying the alert message like: No System Load Data available, can u plz, tell me why it's happening.
Regards
Mark

hi mark,
make sure all the default background jobs are running properly, make sure the following profile parameters are set
stat/as_collect   = 2
stat/as_level =   1
the following specify the maxiimum number of simultaneously existing dialog step or application statistics before the oldest data is deleted.
stat/as_max_files
stat/max_files
you must also activate the individual components of the application statistics by calling st03n and choosing
collector & perf. database -> statistics records & file -> application statistics

ST03N, No System Load Data Available, RSSTAT83, LOGDB_SSCR_NOT_FOUND

Dear SAP Experts
I am unable to execute "ST03N", the message is "No System Load Data Available".
System information said that I have to schedule RSSTAT83 hourly in TCOLL table, and I did that.
(For your information, I also already schedule RSCOLL00 hourly)
But when the job RSSTAT83 run, it was cancelled. The ABAP DUMP says "LOGDB_SSCR_NOT_FOUND". Error in SAP Kernel, The current ABAP "RSSTAT83" program had to be terminated because ABAP processor detected an internal system error. Internal program table SSCR not found. I checked SSCR table through SE11 and the table exists.
Strangely this only happen in my Production system, my Development running well with ST03N
And Yes I have been searching through this forum and Google, but not yet found the solution. The only solution I've got is update my kernel.
Are there any solutions for this problem?
Regards,
Kursteilnehmer

Hi
Your Database Not supported . Please check background job log.
Run se38 and execute RSCOLL00 one by obe via debug mode.
You get the result
Regards
Ravi.S

Music interrupts (system load)

I'm playing my music with the BMP. When the system load gets higher (even for a short time) the music falters and interrupts. This happens even when I open nautilus (or other applications) or when I e.g. copy some data. I'm running gnome 2.8.
Is there a possibility to set process priority or another way to solve such problems?

I'm running kernel 2.6.7 (but I'm downloading a 2.6.8.1 version) and ALSA. PreEmpt is enabled. The system runs on AthlonXP2500 on nForce2 with the onboard sound device. Should I try nvidia's nForce driver?
The problem occurs often when I'm using firefox (especially when I'm downloading stuff with firefox) and openoffice (but more rarely for exemple while running GIMP).
Thank you for your answer...

Massive system load on socket connect

Hi all,
I have some strange problem connecting to a server. I am using the JDK1.4.1 and connect with a timeout of 1000ms, so I would expect Java to honor this, but on some connections the connect call itself takes up to 5 seconds. During this time the processor load goes very hight and the
client is so busy that you cannot even press a button in some GUI.
I have 4 clients which connect to the same socket in parallel but they are all in own threads.
Another thing worth to mention is that I also try to connect to hosts,
where no route exists to them (I need this because I want my system to also work properly when the customer has some errors in his network
configuration and some servers may not be reachable).
Any ideas??

sorry for the missing information:
the problems occur on Windows XP Pers., I havent seen any problems
yet with linux (I'm using Debian) but I don't run the same
configuration on linux (the client side is Windows, the servers all
run on Debian).
The load is definitely operating system load because it occurs when I watch some of the connect()'s block for about 5 seconds - my application does nothing but wait for the connect to come back.

Determining system load

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