Search Results

Search found 4014 results on 161 pages for 'jvm crash'.

Page 11/161 | < Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >

  • Recording for the JVM Diagnostics & Configuration Management sessions

    - by user491905
    Thank you very much for watching my first 2 Oracle Fusion Middleware iDemos. I've recorded the first 2 sessions. Please download the recording from the following links. Troubleshoot Java Memory Leaks with Oracle JVM Diagnostics9 June 2011, 2:04 pm Sydney Time, 53 mins Manage WebLogic Servers by Oracle Enterprise Manager & Configuration Manager16 June 2011, 1:59 pm Sydney Time, 49 minutes I'll publish the presentation slide deck shortly.

    Read the article

  • Recording for the JVM Diagnostics & Configuration Management sessions

    - by ablyth
    Hi All The middleware team have posted recordings of their first 2 sessions from the iDemo series they are running ( MiddlewareTechTalk Blog). Check them out below! Please download the recording from the following links. Troubleshoot Java Memory Leaks with Oracle JVM Diagnostics9 June 2011, 2:04 pm Sydney Time, 53 mins Manage WebLogic Servers by Oracle Enterprise Manager & Configuration Manager16 June 2011, 1:59 pm Sydney Time, 49 minutes Cheers Alex

    Read the article

  • ???????????????????! ????JVM?JRockit?|WebLogic Channel|??????

    - by ???02
    ??    ???????????????????JVM?Oracle JRockit??????????????????????????????????JRockit R28?????Flight Recorder?????????Flight Recorder?????????????????????? ¦??·Oracle WebLogic Server???????????????·??????????·???·Java???????????????????????????????·Oracle JRockit ??·Oracle JRockit Flight Recorder ??·JRockit Flight Recorder????????·JRockit???????????????·JRockit Mission Control????????·WLDF??????????Flight??????????????????????????????????http://www.oracle.com/technetwork/jp/ondemand/application-grid/20100805-jfr-251804-ja.pdf

    Read the article

  • Where and why JVM checks that the return type of entry method main(String args[]) is void and not an

    - by akjain
    I will try to answer both, please correct me if I am wrong: Where: If a static method is being called using Classname.method() or using reflection then it doesn’t matter even if you change the return type of the calling method, the same method will still be called. So JVM probably checks this in one of the native methods of jvm.cpp methodHandle m (THREAD, init_klass-find_method(vmSymbols::object_initializer_name(), vmSymbols::void_method_signature())); if (m.is_null()) { ------ THROW_MSG_0 ……….. Why: Although it’s of useless to return a value from main, as java does not do anything with it but if we try to change the return type of main to int for example, JVM throws public static int main(String[] args) { return 1; } java.lang.NoSuchMethodError: main Exception in thread "main" So may be Java mandates the use of same signature for entry method main() to maintain a symmetry in all Java programs written.

    Read the article

  • Is Apple getting out of the general purpose development platform business?

    - by Charles E. Grant
    I've been doing general ANSI C/Console C++/Java/Web development on Mac hardware for about ten years. I make no claims of objective superiority over other platforms, it just satisfies my personal tastes. With the success of the iPhone and the related App store there was some speculation that Apple would get out of the general purpose computer market, and become a closed software ecosystem, focusing on consumer appliances. I pooh-poohed the speculation at the time, but this week Apple announced that a) they were opening an App store for the Mac, b) Java applications would not be eligible for the App store, c) the Apple JVM was being deprecated and might not be available for future releases of OS X. I'm not a Java developer per se, but I work in a research lab that occasionally writes Java applications, and also depends on tools written Java. This has the potential to be a huge pain in the butt for us. As of now, there is no other JVM for OS X that we can point our end users to. Soy Latte and OpenJDK might be appropriate for developers, but the complexity of the installation makes them inappropriate for end users. Eventually I expect Oracle/SUN will produce a replacement JVM for OS X. More worrisome to me is that Apple used to specifically advertise that it was an excellent platform for scientific development, because they supported all major language platforms. Is the deprecation of their JVM a sign that this market no longer interests them?

    Read the article

  • JVM memory initializazion error after windows update

    - by gianni
    We have three Windows Server 2003 with 2 GB RAM. Server1 tomcat 5.5.25 jvm version SUN 1.6.0_11-b03 Server2 tomcat 5.5.25 jvm version SUN 1.6.0_14-b08 Server3 tomcat 6.0.18 jvm version SUN 1.6.0_14-b08 For the three servers JVM parameters are: -XX:MaxPermSize=256m -Dcatalina.base=C:\Programmi\Apache Group\apache-tomcat-5.5.25 -Dcatalina.home=C:\Programmi\Apache Group\apache-tomcat-5.5.25 -Djava.endorsed.dirs=C:\Programmi\Apache Group\apache-tomcat-5.5.25\common\endorsed -Djava.io.tmpdir=C:\Programmi\Apache Group\apache-tomcat-5.5.25\temp vfprintf -Xms512m -Xmx1024m For some months everithing worked fine. Last friday we installed some windows updates. After the reboot tomcat doesnt start with error: Error occurred during initialization of VM Could not reserve enough space for object heap We reduced the parameter -Xmx1024m to -Xmx768m and now tomcat starts. But we need greater max heap size What happened to our servers ? Thanks in advance.

    Read the article

  • Windows 8 Store App Crash Logs

    - by David Paquette
    I was recently working on a Windows 8 app, and the application was crashing occasionally.  When resuming the application, the app would crash and close immediately without providing any feedback or information on what went wrong.  The crash was very difficult to reproduce, and I could never get the crash to occur when I was debugging through Visual Studio.  My app was crashing, and I had no idea what was going wrong!  HELP!!! After doing some digging, I found that when a Windows 8 Store App crashes, an error is logged in Windows Administrative Events.  You can view the details of any app crash by launching the Event Viewer and selecting Administrative Events under Custom Views.  The Source of the error will be listed as AppHost.  AppHost is the process that runs your Windows 8 Store App.  The error details contain all the information you would expect to find, including a stack trace and line numbers.   Windows 8 Tip:  A shortcut for launching the Event Viewer in Windows 8.  Right click on the bottom left corner of your desktop (where you normally click to go to the Start Screen).  A menu will appear with shortcuts to a number of common system tasks such as Event Viewer, Task Manager, Command Prompt, and Device Manager.

    Read the article

  • Book (or resource) on Java bytecode

    - by Andrea
    I am looking for some resources on the JVM bytecode. Ideally I would for a short book; something more than a blog post but not a 800 pages tome. If it is relevant, I am a Scala developer, not a Java one, although I know Java just fine. I would like something that allowed me to read JVM bytecode and answer questions such as: Why does the bytecode has to know about high level construct such as classes? Are subtyping relations still visible in bytecode? How does type erasure work exactly? How do Oracle and Dalvik bytecode differ, and what consequences does this have for, say, developing Android apps with Scala? How does the JVM manage the stack, and why exactly this creates issues with tail call elimination? and so on.

    Read the article

  • JVM Language Summit 2012 - Registration Open

    - by arungupta
    The 2012 edition of the JVM Languages Summit is Jul 30 - Aug 1, at Oracle's Santa Clara Campus. This is an "an open technical collaboration among language designers, compiler writers, tool builders, runtime engineers, and VM architects". There are presentations, workshops, and lightning talks. About 70 language and VM implementers attended last year and the talks were recorded. Some videos from last year are available here. Check out the Main Page, the Agenda, Logistics, and the Wiki. See the Registration Online; for questions, send mail to inquire AT jvmlangsummit.com.

    Read the article

  • Why does update-notifier contains system-crash-notification?

    - by int_ua
    I just had "System Program Problem Detected" window appearing several times before user session even started (I have KDM with autologin to locked session). I traced it with xprop to being /usr/lib/update-notifier/system-crash-notification which is binary (while I expected it to be some script) and belongs to update-notifier package (while I expected it to be somewhere from apport*). P.S. Clicking on Report problem... button didn't do anything. $ dpkg -s update-notifier | grep Version Version: 0.147 $ dpkg -L update-notifier | grep system-crash /usr/lib/update-notifier/system-crash-notification $ grep RELEASE /etc/lsb-release DISTRIB_RELEASE=13.10

    Read the article

  • Why would I want to use CRaSH?

    - by Adam Tannon
    Justed stumbled across CRaSH and although it looks mighty interesting, I'm wondering why a Java developer should invest time & energy into learning (yet another) shell language. What sort of standard- and cool-applications can CRaSH be used for? Is this like a Groovy-version of Jython? I guess, when the dust settles, I'm looking for CRaSH's "wow" factors. I'm sure they're there, but after spending ~20 minutes perusing the documentation I'm just not seeing them. Thanks in advance!

    Read the article

  • Java Spotlight Episode 35: JVM Performance and Quality

    - by Roger Brinkley
    Tweet Interview with Vladimir Ivanov, Ivan Krylov, Sergey Kuksenko on the JDK 7 Java Virtual Machine performance and quality. Joining us this week on the Java All Star Developer Panel are Dalibor Topic, Java Free and Open Source Software Ambassador, and Alexis Moussine-Pouchkine, Java EE Developer Advocate. Right-click or Control-click to download this MP3 file. You can also subscribe to the Java Spotlight Podcast Feed to get the latest podcast automatically. If you use iTunes you can open iTunes and subscribe with this link: Java Spotlight Podcast in iTunes. Show Notes News Java 7 Launch Event GlassFish 3.1.1 re-planning done, first RC on July 7th, lots of component updates following customer and community feedback Mojarra 2.1.2 is here, just a little ahead of the GlassFish 3.1.1 release. In other JSF-related news, JSF 2.0 has a first expert draft New OpenJDK Project proposed: JDK 7 Update Events June 20-23 JAX, San Jose, CA June 21 Java + MySQL Webinar at 9:00 AM PDT June 21-23 JaZoon, Zurich, Switzerland June 22nd and 28th GlassFish Webinars (one in Portuguese) June 29-July 2 12th Forum Internatioal Software Livre, Porto Alegre, Brazil July 3, Sao Jose do Rio Preto, Brazil July 5, Brasilia, Brazil (DFJUG) July 6, Goiania, Brazil (GOJava) July 6-10 The Developers Conference, Sao Paulo, Brazil July 7 Java 7 Launch Event live in Redwood Shores, CA; Sao Paulo, BR; London, England. July 9, Joao Pessoa, Brazil (PBJUG) July 11, Natal, Brazil (JavaRN) July 14, Fortaleza, Brazil (CEJUG) July 16, Salvador, Brazil (JavaBahia) July 19, Toledo, Brazil (UNIPAR) July 21, Maringa, Brazil (RedFoot) Feature interview This weeks feature interview is with Vladimir Ivanov, HotSpot JVM Quality Engingeer;  Ivan Krylov, Licensee Engineering;  and Sergey Kuksenko, Java SE Performance Team on the JDK 7 Java Virtual Machine peformance and quality. What's Cool Ongoing OpenJDK Bylaws ratification results Show Transcripts Transcript for this show is available here when available

    Read the article

  • How do I troubleshoot hardware issues related to a computer freeze/crash?

    - by KronoS
    What are some common guidelines and issues related to hardware being the issue of a computer crash? What should I look for and how do I troubleshoot these problems? What are some tools that are useful in diagnosing these hardware related crashes? I am looking to be able to isolate the problematic device with specific tools and guidelines. For example if device X is causing system failure how do I go about diagnosing it?

    Read the article

  • Netbeans doesn't start, Java fatal error, unless sudo

    - by elect
    Fresh 13.10 64b Openjdk 6 is there, I just installed Netbeans 7.01 from the repo, but it doesn't work, I open then a console elect@elect-desktop:~$ netbeans # # A fatal error has been detected by the Java Runtime Environment: # # SIGSEGV (0xb) at pc=0x00007faebdf79325, pid=5251, tid=140388628424448 # # JRE version: 6.0_27-b27 # Java VM: OpenJDK 64-Bit Server VM (20.0-b12 mixed mode linux-amd64 compressed oops) # Derivative: IcedTea6 1.12.6 # Distribution: Ubuntu Saucy Salamander (development branch), package 6b27-1.12.6-1ubuntu2 # Problematic frame: # C [libgobject-2.0.so.0+0x14325] g_cclosure_marshal_BOOLEAN__BOXED_BOXEDv+0x985 # # An error report file with more information is saved as: # /home/elect/hs_err_pid5251.log [thread 140386948781824 also had an error] # # If you would like to submit a bug report, please include # instructions how to reproduce the bug and visit: # https://bugs.launchpad.net/ubuntu/+source/openjdk-6/ # /usr/share/netbeans/7.0.1/bin/../platform/lib/nbexec: line 548: 5251 Aborted (core dumped) "/usr/lib/jvm/java-6-openjdk-amd64/bin/java" -Djdk.home="/usr/lib/jvm/java-6-openjdk-amd64" -Djava.library.path=/usr/lib/jni -classpath "/usr/share/netbeans/7.0.1/platform/lib/boot.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-modules.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-util.jar:/usr/share/netbeans/7.0.1/platform/lib/org-openide-util-lookup.jar:/usr/lib/jvm/java-6-openjdk-amd64/lib/dt.jar:/usr/lib/jvm/java-6-openjdk-amd64/lib/tools.jar" -Dnetbeans.system_http_proxy="DIRECT" -Dnetbeans.system_http_non_proxy_hosts="" -Dnetbeans.dirs="/usr/share/netbeans/7.0.1/nb:/usr/share/netbeans/7.0.1/bin/../ergonomics:/usr/share/netbeans/7.0.1/ide:/usr/share/netbeans/7.0.1/java:/usr/share/netbeans/7.0.1/bin/../xml:/usr/share/netbeans/7.0.1/apisupport:/usr/share/netbeans/7.0.1/bin/../webcommon:/usr/share/netbeans/7.0.1/bin/../websvccommon:/usr/share/netbeans/7.0.1/bin/../enterprise:/usr/share/netbeans/7.0.1/bin/../mobility:/usr/share/netbeans/7.0.1/bin/../profiler:/usr/share/netbeans/7.0.1/bin/../ruby:/usr/share/netbeans/7.0.1/bin/../python:/usr/share/netbeans/7.0.1/bin/../php:/usr/share/netbeans/7.0.1/bin/../visualweb:/usr/share/netbeans/7.0.1/bin/../soa:/usr/share/netbeans/7.0.1/bin/../identity:/usr/share/netbeans/7.0.1/bin/../uml:/usr/share/netbeans/7.0.1/harness:/usr/share/netbeans/7.0.1/bin/../cnd:/usr/share/netbeans/7.0.1/bin/../dlight:/usr/share/netbeans/7.0.1/bin/../groovy:/usr/share/netbeans/7.0.1/bin/../extra:/usr/share/netbeans/7.0.1/bin/../javafx:/usr/share/netbeans/7.0.1/bin/../javacard:" -Dnetbeans.home="/usr/share/netbeans/7.0.1/platform" '-Dnetbeans.importclass=org.netbeans.upgrade.AutoUpgrade' '-Dnetbeans.accept_license_class=org.netbeans.license.AcceptLicense' '-XX:MaxPermSize=384m' '-Xmx768m' '-client' '-Xss2m' '-Xms32m' '-XX:PermSize=32m' '-Dapple.laf.useScreenMenuBar=true' '-Dapple.awt.graphics.UseQuartz=true' '-Dsun.java2d.noddraw=true' '-Dsun.java2d.pmoffscreen=false' -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath="/home/elect/.netbeans/7.0/var/log/heapdump.hprof" org.netbeans.Main --userdir "/home/elect/.netbeans/7.0" "--branding" "nb" 0<&0 Looking around, the second answer, here Vigintas Labakojis, points out something regarding permission, I just try sudo netbeans, it works.. Then I look for the ~/.cache/netbeans/ I dont have, I have instead ~/.netbeans/ Then I run his commands on those folder, it doesn't work.. It must be something else, do you have any idea? In any case, my log /home/elect/hs_err_pid5251.log is here

    Read the article

  • Metro apps crash on startup, driver or permissions issue?

    - by Vee
    After installing Win8 x64 RC, Metro apps worked correctly, but desktop OpenGL apps were slow and unresponsive. I installed the latest Win8 nVidia drivers, and the OpenGL apps started working correctly. At the same time, because of annoying permission messages, I changed the C:\ drive and all its files ownerships to my user, and gave it full permission. I restarted my pc after installing the drivers, and now Metro apps only show the splash screen, then crash. I tried installing other versions of the nVidia drivers, with the same result. My GPU is a GeForce GTX275. Is this a known problem with nVidia drivers? Or maybe changing the ownership of C:\ is the real problem? Thank you. More information (after looking in the event viewer) I've managed to find the problem and the error in the Event Viewer. I still cannot solve it. Here's the information I found by opening the Mail app and letting it crash: Log Name: Microsoft-Windows-TWinUI/Operational Source: Microsoft-Windows-Immersive-Shell Date: 07/06/2012 15.54.17 Event ID: 5961 Task Category: (5961) Level: Error Keywords: User: VEE-PC\Vittorio Computer: vee-pc Description: Activation of the app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail for the Windows.Launch contract failed with error: The app didn't start.. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" /> <EventID>5961</EventID> <Version>0</Version> <Level>2</Level> <Task>5961</Task> <Opcode>0</Opcode> <Keywords>0x4000000000000000</Keywords> <TimeCreated SystemTime="2012-06-07T13:54:17.472416600Z" /> <EventRecordID>6524</EventRecordID> <Correlation /> <Execution ProcessID="3008" ThreadID="6756" /> <Channel>Microsoft-Windows-TWinUI/Operational</Channel> <Computer>vee-pc</Computer> <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" /> </System> <EventData> <Data Name="AppId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data> <Data Name="ContractId">Windows.Launch</Data> <Data Name="ErrorCode">-2144927141</Data> </EventData> </Event> Found other stuff, this is another error that appears when opening a Metro app: Log Name: Application Source: ESENT Date: 07/06/2012 16.01.00 Event ID: 490 Task Category: General Level: Error Keywords: Classic User: N/A Computer: vee-pc Description: svchost (1376) SRUJet: An attempt to open the file "C:\Windows\system32\SRU\SRU.log" for read / write access failed with system error 5 (0x00000005): "Access is denied. ". The open file operation will fail with error -1032 (0xfffffbf8). Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="ESENT" /> <EventID Qualifiers="0">490</EventID> <Level>2</Level> <Task>1</Task> <Keywords>0x80000000000000</Keywords> <TimeCreated SystemTime="2012-06-07T14:01:00.000000000Z" /> <EventRecordID>11854</EventRecordID> <Channel>Application</Channel> <Computer>vee-pc</Computer> <Security /> </System> <EventData> <Data>svchost</Data> <Data>1376</Data> <Data>SRUJet: </Data> <Data>C:\Windows\system32\SRU\SRU.log</Data> <Data>-1032 (0xfffffbf8)</Data> <Data>5 (0x00000005)</Data> <Data>Access is denied. </Data> </EventData> </Event> After changing permissions again (adding Everyone and Creator Owner to System32), the "access denied to sru.log" error disappears, but this one appears in its place: Log Name: Application Source: Microsoft-Windows-Immersive-Shell Date: 07/06/2012 16.16.34 Event ID: 2486 Task Category: (2414) Level: Error Keywords: (64),Process Lifetime Manager User: VEE-PC\Vittorio Computer: vee-pc Description: App microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail did not launch within its allotted time. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" /> <EventID>2486</EventID> <Version>0</Version> <Level>2</Level> <Task>2414</Task> <Opcode>0</Opcode> <Keywords>0x2000000000000042</Keywords> <TimeCreated SystemTime="2012-06-07T14:16:34.616499600Z" /> <EventRecordID>11916</EventRecordID> <Correlation /> <Execution ProcessID="3008" ThreadID="6996" /> <Channel>Application</Channel> <Computer>vee-pc</Computer> <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" /> </System> <EventData> <Data Name="ApplicationId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data> </EventData> </Event> Now I'm stuck. It tells me "Activation of app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail failed with error: The app didn't start. See the Microsoft-Windows-TWinUI/Operational log for additional information." but I can't find the Microsoft-Windows-TWinUI/Operational log. I'm starting a bounty. I found the TWinUI/Operational log. It only tells me: Log Name: Microsoft-Windows-TWinUI/Operational Source: Microsoft-Windows-Immersive-Shell Date: 07/06/2012 16.28.57 Event ID: 5961 Task Category: (5961) Level: Error Keywords: User: VEE-PC\Vittorio Computer: vee-pc Description: Activation of the app microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail for the Windows.BackgroundTasks contract failed with error: The app didn't start.. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-Immersive-Shell" Guid="{315A8872-923E-4EA2-9889-33CD4754BF64}" /> <EventID>5961</EventID> <Version>0</Version> <Level>2</Level> <Task>5961</Task> <Opcode>0</Opcode> <Keywords>0x4000000000000000</Keywords> <TimeCreated SystemTime="2012-06-07T14:28:57.238140800Z" /> <EventRecordID>6536</EventRecordID> <Correlation /> <Execution ProcessID="3008" ThreadID="2624" /> <Channel>Microsoft-Windows-TWinUI/Operational</Channel> <Computer>vee-pc</Computer> <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" /> </System> <EventData> <Data Name="AppId">microsoft.windowscommunicationsapps_8wekyb3d8bbwe!Microsoft.WindowsLive.Mail</Data> <Data Name="ContractId">Windows.BackgroundTasks</Data> <Data Name="ErrorCode">-2144927141</Data> </EventData> </Event> I need to go deeper. I found a forum thread that told me to look for "DCOM" errors. I found this one related to the app crash "The server Microsoft.WindowsLive.Mail.wwa did not register with DCOM within the required timeout." Log Name: System Source: Microsoft-Windows-DistributedCOM Date: 07/06/2012 16.46.45 Event ID: 10010 Task Category: None Level: Error Keywords: Classic User: VEE-PC\Vittorio Computer: vee-pc Description: The server Microsoft.WindowsLive.Mail.wwa did not register with DCOM within the required timeout. Event Xml: <Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event"> <System> <Provider Name="Microsoft-Windows-DistributedCOM" Guid="{1B562E86-B7AA-4131-BADC-B6F3A001407E}" EventSourceName="DCOM" /> <EventID Qualifiers="0">10010</EventID> <Version>0</Version> <Level>2</Level> <Task>0</Task> <Opcode>0</Opcode> <Keywords>0x8080000000000000</Keywords> <TimeCreated SystemTime="2012-06-07T14:46:45.586943800Z" /> <EventRecordID>2763</EventRecordID> <Correlation /> <Execution ProcessID="804" ThreadID="2364" /> <Channel>System</Channel> <Computer>vee-pc</Computer> <Security UserID="S-1-5-21-2753614643-3522538917-4071044258-1001" /> </System> <EventData> <Data Name="param1">Microsoft.WindowsLive.Mail.wwa</Data> </EventData> </Event>

    Read the article

  • Inverted schedctl usage in the JVM

    - by Dave
    The schedctl facility in Solaris allows a thread to request that the kernel defer involuntary preemption for a brief period. The mechanism is strictly advisory - the kernel can opt to ignore the request. Schedctl is typically used to bracket lock critical sections. That, in turn, can avoid convoying -- threads piling up on a critical section behind a preempted lock-holder -- and other lock-related performance pathologies. If you're interested see the man pages for schedctl_start() and schedctl_stop() and the schedctl.h include file. The implementation is very efficient. schedctl_start(), which asks that preemption be deferred, simply stores into a thread-specific structure -- the schedctl block -- that the kernel maps into user-space. Similarly, schedctl_stop() clears the flag set by schedctl_stop() and then checks a "preemption pending" flag in the block. Normally, this will be false, but if set schedctl_stop() will yield to politely grant the CPU to other threads. Note that you can't abuse this facility for long-term preemption avoidance as the deferral is brief. If your thread exceeds the grace period the kernel will preempt it and transiently degrade its effective scheduling priority. Further reading : US05937187 and various papers by Andy Tucker. We'll now switch topics to the implementation of the "synchronized" locking construct in the HotSpot JVM. If a lock is contended then on multiprocessor systems we'll spin briefly to try to avoid context switching. Context switching is wasted work and inflicts various cache and TLB penalties on the threads involved. If context switching were "free" then we'd never spin to avoid switching, but that's not the case. We use an adaptive spin-then-park strategy. One potentially undesirable outcome is that we can be preempted while spinning. When our spinning thread is finally rescheduled the lock may or may not be available. If not, we'll spin and then potentially park (block) again, thus suffering a 2nd context switch. Recall that the reason we spin is to avoid context switching. To avoid this scenario I've found it useful to enable schedctl to request deferral while spinning. But while spinning I've arranged for the code to periodically check or poll the "preemption pending" flag. If that's found set we simply abandon our spinning attempt and park immediately. This avoids the double context-switch scenario above. One annoyance is that the schedctl blocks for the threads in a given process are tightly packed on special pages mapped from kernel space into user-land. As such, writes to the schedctl blocks can cause false sharing on other adjacent blocks. Hopefully the kernel folks will make changes to avoid this by padding and aligning the blocks to ensure that one cache line underlies at most one schedctl block at any one time.

    Read the article

  • What could be the Java successor Oracle wants to invest in?

    - by deamon
    I've read that Oracle wants to invest into another language than Java: "On the other hand, Oracle has been particularly supportive of alternative JVM languages. Adam Messinger ( http://www.linkedin.com/in/adammessinger ) was pretty blunt at the JVM Languages Summit this year about Java the language reaching it's logical end and how Oracle is looking for a 'higher level' language to 'put significant investment into.'" But what language could be the one Oracle wants to invest in? Is there another candidate than Scala?

    Read the article

  • Java Terms that are Plagued with Vaguery

    - by Adam Tannon
    What's the difference between a Java Process (what your OS sees) and a JVM? Are they one in the same or are they actually different? How are the JRE and JDK different (in purpose and file content), and which one contains the libraries for Java SE? What's the difference between the Java "Runtime" and a JVM? These are questions I've been asking myself (and colleagues) for years and everybody seems to have very different answers.

    Read the article

  • Java heap space

    - by java_mouse
    In Java/JVM, why do we call the memory place where Java creates objects as "Heap"? Does it use the Heap Data Structure to create/remove/maintain the objects? As I read in the documentation of Heap data structure, the algorithm compares the objects with existing nodes and places them in such a way that Parent object is "greater" than the children. ( Or "lesser" in case of min heap). So in JVM, how are the objects compared against each other before placing them in the heap?

    Read the article

  • How can I recover Google Chrome extensions, settings after a Linux crash?

    - by Norman Ramsey
    I'm running Google Chrome 5.0.307.11 (Official Build 39572) beta on Debian Linux (lenny) kernel version 2.6.26-2-686. The machine is a laptop (Lenovo Thinkpad X300) and sometimes it freezes, usually shortly after wakeup from sleep. The only cure is the power button, but when I restart my Google Chrome web browser after such an event, Settings on the Options menu revert to defaults. Chrome removes all the extensions from ~/.config/google-chrome/Default/Extensions, leaving me with no extensions. The set of "pages last open" is lost. I'd love to know how to poke at the file system in order to recover any or all of this information, especially my extensions. It is a pain to re-do everything by hand each time. How can I recover Google Chrome's extensions and settings after a Linux crash?

    Read the article

  • Why is the JVM stack-based and the DalvikVM register based?

    - by aioobe
    I'm curious, why did Sun decide to make the JVM stack-based and Google decide to make the DalvikVM register based? I suppose the JVM can't really assume that a certain number of registers are available on the target platform, since it is supposed to be platform independent. Therefor it just postpones the register-allocation etc, to the JIT compiler. (Correct me if I'm wrong.) So the Android guys thought, "hey, that's inefficient, let's go for a register based vm right away..."? But wait, there are multiple different android devices, what number of registers did the Dalvik target? Are the Dalvik opcodes hardcoded for a certain number of registers? Do all current Android devices on the market have about the same number of registers? Or, is there a register re-allocation performed during dex-loading? How does all this fit together?

    Read the article

  • Is there a way to tell JVM to optimize my code before processing?

    - by Rogach
    I have a method, which takes much time to execute first time. But after several invocations, it takes about 30 times less time. So, to make my application respond to user interaction faster, I "warm-up" this method (5 times) with some sample data on initialization of application. But this increases app start-up time. I read, that JVM's can optimize and compile my java code to native, thus speeding things up. I wanted to know - maybe there is some way to explicitly tell JVM that I want this method to be compiled on startup of application?

    Read the article

< Previous Page | 7 8 9 10 11 12 13 14 15 16 17 18  | Next Page >