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Conference vaxaxp::alphanotes

Title:Alpha Support Conference
Notice:This is a new Alphanotes, please read note 2.2
Moderator:VAXAXP::BERNARDO
Created:Thu Jan 02 1997
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:128
Total number of notes:617

92.0. "Poor performance on Alpha" by GALVIA::MCCARTHY_M () Wed Apr 30 1997 06:21

    I am involved in a migration project from VAX to ALPHA, the performance
    of the Alpha kit is quite good however any processes which are spawned
    off by the application seem to take quite a while to get up and running
    compared to the VAX kit.
    
    Does anybody know off-hand what my problem may be or how I can overcome
    it.
    
    Thanks Mick
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92.1profile the code...XDELTA::HOFFMANSteve, OpenVMS EngineeringWed Apr 30 1997 10:4121
   Check the working set specified for the created processes, and check
   the process quotas for sufficient values, and check for sufficient
   free memory on the system, etc.

   If there are no quotas specified in the call to sys$creprc or lib$spawn,
   seriously consider adding the list of(minimum) required quotas -- one
   inherits the SYSGEN minimum and/or default values, which may or may not
   reflect specific application requirements.

   Also note that lib$spawn is traditionally a slow operation, and more
   particularly slow when large numbers of symbols and logical names
   are copied into the context of the subprocess.

   If nothing obvious shows from the above checks, you will likely want
   to characterize where the application is spending its time and compare
   these timings with the VAX implementation of the application, using
   some simple application-specific profiling and/or logging tools. 
   (Imbeded calls to lib$show_timer, et al., at the simplest, or some
   slightly more advanced logging and debug-tracing support.)  (Without
   this profiling information, we're all guessing...)
92.2Image activation?STAR::DIPIRROWed Apr 30 1997 11:497
    	If the spawned subprocesses are running images which require a lot
    fo shareable images to be mapped at image activation time, then this
    might be the problem. Image activation can sometimes be slower on Alpha
    with lots of shareable images, but once things get going, you should
    see the speed increase. There are also some things you can do to speed
    this up, but I know there's at least one note in here that talks about
    image activation times.