[wpkg-users] [Bug 233] Command invokations cause unneccessary delays

Tue Aug 2 02:32:50 CEST 2011

http://bugzilla.wpkg.org/show_bug.cgi?id=233

Rainer Meier <r.meier at wpkg.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |r.meier at wpkg.org
         Resolution|                            |FIXED

--- Comment #1 from Rainer Meier <r.meier at wpkg.org>  ---
Thanks for the input. In fact I've invested slightly more time to implement a
dynamic algorithm.
In fact the algorithm now starts with 10ms polling time. After 100ms it
increases to 100ms polling time. After 1s it falls back to 1s polling time.

As a result short-running tasks will make WPKG terminate almost immediately
while on long-running tasks WPKG prevents hogging the CPU for polling purposes.
The idea is that for long-running tasks (minutes?) it does not matter whether
WPKG at maximum takes 1s longer to complete while for short-running tasks (<1s)
it might matter).

I've tried different values and using shorter polling times than 10ms do not
really provide any real speed up.

As you can see from the comparison below WPKG 1.2.1-RC6 did take around 1:42 in
my tests (extended to 100 checks). With your modification the execution dime
went down to ~0:12. With my changes proposed for version 1.2.1-RC7 I've managed
to reach ~0:03. Well, from almost 2 minutes to 2 second it is definitely a big
step.

Please note that this test case is a very extreme case where 100 commands are
executed which all are supposed to terminate within a few ms run time. In
practical most packages will not be handled significantly faster.

FIX: Fixed long execution run times if many short-running external commands are
     invoked. For example if many execute-style checks were invoked and each
     check finished its task in less than 1s time, then WPKG would wait at
     least 1 second for it to finish. Unfortunately WSH is not very advanced in
     handling child processes but the algorithm has been changed in a way that
     for the first 100ms of run time the child status is checked every 10ms.
     For the next 1000ms the status is checked every 100ms. If the task is not
     finished by then the task will be checked for termination once per second.
     This allows short-running tasks to terminate quickly while preventing high
     WPKG load for monitoring on long-lasting tasks.
     Fixes bug 233. Thanks to Malte Starostik für suggestion.

Download it here:
<http://wpkg.svn.sourceforge.net/viewvc/wpkg/wpkg/stable/1.2/>

Comparison:

Results using 100 trivial checks of type "<check type="execute" path="cmd
/cecho."/>".

2011-08-02 02:23:08, STATUS  : Starting software synchronization
2011-08-02 02:23:08, STATUS  : Number of packages to be removed: 0
2011-08-02 02:23:08, STATUS  : Install: Verifying package 'Execution Speed
Demo' (1/1)
2011-08-02 02:24:49, STATUS  : Finished software synchronization

real    1m42.478s
user    0m0.015s
sys     0m0.015s

2011-08-02 02:21:20, STATUS  : Starting software synchronization
2011-08-02 02:21:20, STATUS  : Number of packages to be removed: 0
2011-08-02 02:21:20, STATUS  : Install: Verifying package 'Execution Speed
Demo' (1/1)
2011-08-02 02:21:31, STATUS  : Finished software synchronization

real    0m11.313s
user    0m0.000s
sys     0m0.031s

2011-08-02 02:22:03, STATUS  : Starting software synchronization
2011-08-02 02:22:03, STATUS  : Number of packages to be removed: 0
2011-08-02 02:22:03, STATUS  : Install: Verifying package 'Execution Speed
Demo' (1/1)
2011-08-02 02:22:05, STATUS  : Finished software synchronization

real    0m2.524s
user    0m0.000s
sys     0m0.031s

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