Re: Ada.Execution_Time

[anon@att.net]

In <iejsu9$lct$1@news.eternal-september.org>, BrianG <briang000@gmail.com> writes:
>anon@att.net wrote:
>> In <ie91co$cko$1@news.eternal-september.org>, BrianG <briang000@gmail.com> writes:
>>> Georg Bauhaus wrote:
>>>> On 12/12/10 10:59 PM, BrianG wrote:
>....
>[Lots of meaningless comments deleted.]
>> For the average Ada programmer, its another Ada package that most will 
>> never use because they will just use Ada.Real_Time.  
>[etc.]
>>  In some cases the Ada.Execution_Time
>> package can replace the Ada.Real_Time with only altering the with/use 
>> statements.
>If you mean that they both define a Clock and a Split, maybe.  If you mean
>any program that actually does anything, that's not possible.  That was my
>original comment:  Execution_Time does not provide any types/operations
>useful, without also 'with'ing Real_Time.
>> 
>[etc.]
>(Don't know why I bother w/ this msg.)


Kind of funny you cutting down "TOP" which can be found on most Linux 
boxes  Which allow anyone with the CPU options turn on to see both the 
Real_Time and CPU_Time.

An Example: Just use you your favorite music/video player and play a 2 
min song.  Real_Time will show the 2 min for the song and the 1 to 3 
seconds for the CPU_Time. 

And I know one professor that is now station in Poland that did enjoy 
giving his student assignment to decrease the amount of CPU execution 
time that an algorithm used. Which meant a student normally had to 
rewrite the algorithm. His student just loved him for that!


Note: Not sure of the name for the Windows version of Linux's top.


As for "Pragmas" that may effect the "CPU Execution Time. 
Three may pragmas that have been disabled in GNAT and they are:

    pragma Optimize     :  Gnat uses gcc command line -O(0,1,2,3.4).
                           Which does effect compiler language 
                           translation.

    pragma System_Name  :  Gnat uses default or gcc command line to 
    pragma Storage_Unit :  determine target. Target processor and its 
                           normal data size can effect CPU time.



And for web Servers:

Check with any main web hosting for the "Terms" or "Agreement".  In 
the document you will see a paragraph that states the web site excess 
from 10 to 25% of the resources will be shutdown.

Examples: 

    From Host: http://www.micfo.com/agreement

    6 SERVER RESOURCE USAGE


        The Client agrees to utilize "micfo's" Server Resources as set 
        out in clause 6.2.1, 6.2,2:

    6.2.1
        Shared Hosting; 7% of the CPU in any given twenty two (22) 
        Business Days.
    6.2.2
        Reseller Hosting; 10% of the CPU in any given twenty two 
        (22) Business Days.


        Also: from Host: http://www.hostgator.com/tos/tos.php

        User may not: 

        1) Use 25% or more of system resources for longer then 90 
           seconds. There are numerous activities that could cause 
           such problems; these include: CGI scripts, FTP, PHP, 
           HTTP, etc.

       12) Only use https protocol when necessary; encrypting and 
           decrypting communications is noticeably more CPU-intensive 
           than unencrypted communications.


How to you think these or any other web hosting company could measure the 
complete system resources without measuring the CPU Execution Time on a 
given user or application! In Ada, the routines can now use the package 
called "Ada.CPU_Execution_Time".