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PH03721: High CPU usage in node.js event loop

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APAR status

  • Closed as program error.

Error description

  • From the system trace in a dump of a high CPU scenario, it is
evident that the node.js run-time is alternately calling
msgrcv() and poll() out of uv__io_poll().

Local fix

  • 



Problem summary


    

  • ****************************************************************
* USERS AFFECTED: All users of the IBM SDK for Node.js -       *
*                 z/OS, V6.0                                   *
****************************************************************
* PROBLEM DESCRIPTION: Intermittent high CPU usage within      *
*                      Node.js applications                    *
****************************************************************
* RECOMMENDATION: Apply provided service                       *
****************************************************************
The asynchronous I/O library within the Node.js runtime fails
to distinguish events where the file descriptor IDs happens to
match the message queue ID.  As a result, a poll() call may be
invoked with an incorrect file descriptor, resulting in a CPU
busy loop within the function epoll_wait().

    



Problem conclusion


    

  • The Node.js runtime has been fixed to distinguish between the
source of the event to prevent the problematic scenario.

    



Temporary fix


    

  • 



Comments


    

  • ×**** PE18/10/17 PTF IN ERROR. SEE APAR PH04013  FOR DESCRIPTION

    



APAR Information




    

  • APAR number
    PH03721
    • 

  • Reported component name
    SDK FOR NODE.JS
    • 

  • Reported component ID
    5655SDK00
    • 

  • Reported release
    600
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2018-10-05
    • 

  • Closed date
    2018-10-09
    • 

  • Last modified date
    2018-11-01
    • 





    

  • APAR is sysrouted FROM one or more of the following:
    

    • 

  • APAR is sysrouted TO one or more of the following:
    

    
UI58997
    

    • 



Modules/Macros


    

  • CNJPHPAX CNJSNPAX

    



Fix information


    

  • Fixed component name
    SDK FOR NODE.JS
    • 

  • Fixed component ID
    5655SDK00
    • 



Applicable component levels


    

  • R600  PSY  UI58997
       UP18/11/01  P  F810
    • 



Fix is available


    

  • Select the PTF appropriate for your component level.
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              [{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"600","Edition":"","Line of Business":{"code":"","label":""}},{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSWLKB","label":"IBM SDK for Node.js"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"600","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]
              

                                                                    

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            28 April 2021
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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