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Conference noted::decps

Title:POLYCENTER Performance Data Collector & Advisor for OpenVMS
Notice:Latest version V2.2-51
Moderator:BSS::JILSON
Created:Wed Nov 07 1990
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2413
Total number of notes:9017

2380.0. "DIOs includes disk ios ?" by BACHUS::PETRIOLI () Wed Jan 29 1997 10:09

    
    If I look at custom - by image graths I can see the diskio and direct
    io a given image is doing. However, does the direct io number includes
    the diskio number ? ie, if the image is doing 50 diskio/sec and also 50
    direct io/sec, should I consider that the image does 50 diskios + 50
    direct io to some other non-disk devices or should I consider the image
    is doing 50 direct io/sec, all 50 of them being diskio ?
    
    And finaly are, tcpip ios counted as direct ios ?
    
    Thanks for help.
    
    /al
T.RTitleUserPersonal
Name		DateLines
2380.1BSS::JILSONWFH in the Chemung River ValleyWed Jan 29 1997 11:419
Disk IO is a subset of direct IO.  In your example 50 disk IO & 50 direct 
IO means that all the direct IO is disk IO.  If you had 25 disk IO and 25 
non-disk direct IO, you would have 50 direct IO and 25 disk IO.

Whether an IO is considered direct or buffered is the job of the driver, it 
is not a job of $QIO.  For UCX, yes some TCP/IP IO is classified as direct 
IO by the UCX drivers.

Jilly
2380.2Thanks.BACHUS::PETRIOLIThu Jan 30 1997 02:244
    
    Thanks for your quick and clear answer Jilly.
    
    /Al