How to delay execution?

I have several loops. I need to delay each round of execution in those loops by a specified time interval. This is quite easy in C,C++ where we just use delay() function as one statement inside the loop. Is there any equivalence in Java?
The solution of using Timer is not acceptable, as it makes the things too complicated compared to just using one function.
I'd appreciate for the better solution.
Thank you.

Hi Raju,
Are you familiar with the "sleep()" method in class "java.lang.Thread"?
Here is a link to the javadoc:
http://java.sun.com/j2se/1.4.1/docs/api/java/lang/Thread.html#sleep(long)
Is this what you were looking for?
Hope it helps.
Good Luck,
Avi.

Similar Messages

How to extract execution time of a step

how to extract execution time of a step ?
This step calls another sequence, and
I want to know how long it take to execute that seqeuence.
I need this information during run time, not in the
report.
thanks.

Hi,
You could try.
Enable the Record Result for the step in question.
This will allow you to extract the TotalTime.
Then you could use the RemoveElements(Locals.ResultList,"[0]",1) - this assumes you have only logged one result. This is the same as not recording results for that step.
Otherwise you will have to workout the time yourself by calling the API Execution.SecondsExecuting() - API Execution.SecondsAtStart().
Regards
Ray Farmer
Regards
Ray Farmer

How to break execution when Modal SubVI opened?

Colleagues,
A very simple question: sometimes I have modal dialogs, which cannot be closed (this may happened during programming, when logic not completed, or if one of then modal dialogs was opened, and then main VI was started). So, when it happened, then the only way to break execution is killing LabVIEW from Task Manager. I remember that was a simple trick how to stop execution without killing LabVIEW, but can't remember. Can you please give me a hint - how to stop execution in such situation? Yes, I know about Ctrl+. combination, but this doesn't work in this case.
See attachment for details.
Andrey.
Solved!
Go to Solution.
Attachments:
Modal SubVI.zip ‏8 KB

Try pressing "Ctrl + ." (period) to stop the VI.
Now is the right time to use %^<%Y-%m-%dT%H:%M:%S%3uZ>T
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Inplaceness is synonymous with insidiousness

How to delay the license days in XI-NW2004s?

I have successfully installed the XI-NW2004s,but only used in 30days.
I think I can adjust time back to setup day to use longer. To my disappointed, there were many j2ee service failed in Visual J2EE administrator.
How to delay the license days in J2EE service ?
Can I install a temp license in Tcode "slicense" just like Minisap developer?
Thx !
points will be award !
best regard!

Hi Raymond,
You need to make sure that the date to which you are changing should be greater then the date of installation. why don't you try this
1.Use <b>SU01</b> transaction to find the date when the user was created.
2. Now change the system date to that particular date or one day greater.
Make sure all the instances of 2004's are down before changing the system date.
once done restart the system.
That should work.....
Regards
Gopi

How can delayed delivery update be configured for Inbound delivery ?

Hi All,
How can delayed delivery update be configured for Inbound delivery ?
There is setting for Outbound delivery delayed delivery update but how the same functionality be used for Inbound delivery?
Regards
Jimmi

Hello Jimmi,
Unfortunately I must confirm that the Delayed delivery update is only available for outbound deliveries. Please see below note for further details
664316 Tips for the delayed delivery update for TO
I hope this information helps!
Martin

How to delay stream

hi all
is there any suggestion of how to delay streaming between source and destination database
i have site A to stream it in Site B but not immediately , i want to delay it to define date time.

Try changing the codec it might be quicker to encode video using a different format, I'm not a massive fan of wmv tbh.
http://www.linux.org/docs/ldp/howto/Vid … /x988.html
For more information.

How to stop execution in while loop without stopping execution of other loops in the same vi

HI
I am quite a novice in Labview.
I have a problem in my project. I used a while loop inside my vi to build an array of ten values along with other loops. Then I used a stop button to stop manually the while loop. But it seems like the loop doesn't stop in the middle of the array building and so other loops in the vi doesn't work until the while loop finishes building the array and as soon as while loop execution is over, the complete vi stops. But all that I wanted was to build the array using the shift register along with the control to stop building array anytime. And not to stop execution of other structures when the while loop finishes.
Can anyone help me?
Rahul

Hi Rahul,
Modified ur Vi to work with single button.
But the subtract case is not in any loop.
So, once both the loops stop, the subtract case will execute only once. Depending on state of subtaract boolean at that time, corresponding case will be executed and the Vi will stop.
so think of a logic where u can put this also in a new loop.
Or you can also incorporate it in one of the two loops and pass the other loop's data to it.
Let us know how you will proceed in this regard
I am posting your VI as well a VI with my modifications VI in Labview 7.0 so that Thomas can give his suggestions too
Plus, always keep a time delay in your while loops.
Oh sorry, the "arrayinouttestnewfinal.vi" is the modified vi
Regards
Dev
Message Edited by devchander on 01-10-2006 06:15 AM
Message Edited by devchander on 01-10-2006 06:19 AM
Attachments:
arrayinouttestnewfinalnew4.vi ‏59 KB
arrayinouttestnewfinal.vi ‏63 KB

How to delay an DB Update

Hi,
I would like to know if there is a possibility to delay an asynchronous update to the database?
What I mean by that? I have changed or created some data in the UI, in my case in the CRM application, and than when saving, I am triggering the COMMIT WORK statement, not in the local task. So, the Update will be executed in the Update LUW, and the application can run forward without having to wait for the DB update.
And now, without having to change coding, I would like to simulate a case where either the database connection is not available, or maybe all the Update LUW's are busy or others. How can I achieve this?
To deactivate the update process using the tx sm13 is not an option to me, as this will effect all users. I would like to have a solution user dependent.
Also, I could change my update function module, by adding an WAIT UP TO x SECONDS statement. But I would like to avoid this as well.
Would appriciate any input...
Enjoy your day,
Erika

Hi,
Instead of using WAIT UP TO x SECONDS try to use inbackground task ..
this will do the commit work at the end of program execution.
if LUW fails the update also fails for your function module
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Prabhudas

How to delay the exection of an interface

Hi Experts,
I have a file to file scenario. There are two such interfaces.
I want to introduce a delay in the execution of one interface.
I have tried using sleep function in the mapping, but its not to mch effect.
Is there ne way we can do it??? how abt OS command after/before execution??
what should the script be?
pls share your thughts
Regards,
Teja

divyesh vasani wrote:
With OS Script, in the second interface before message processing option in adapter, you can use choice command in batch script.
>
> Find some links on Choice command in batch.
>
>
>
> ---Div
Managed to find the anatomy of choice command in batch file to introduce delay:
Choice command in DOS is used to select menu items.
Here you can use with below syntax in OS command before processing in second interface, sender file adapter
choice /C:a /D:a /T:2>nul
Where 2 is the delay in seconds and keep rest as them.
I tested on windows XP on dos command.
--Div

How to delay creation of VideoDisplay

My Flex' app reads an xml with different video-source-url's.
On the same time the VideoDisplay is created. But it does not have
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taking to long.
How can I delay the creation of the VideoDisplay component?

"Flextoth" <[email protected]> wrote in
message
news:glktfo$ipm$[email protected]..
> My Flex' app reads an xml with different
video-source-url's. On the same
> time
> the VideoDisplay is created. But it does not have the
url for the
> VideoDisplay
> source property because parsing is taking to long.
>
> How can I delay the creation of the VideoDisplay
component?
>
Do you actually need to delay its creation, or just delay
setting its source
property?

How to get execution plan in a CLOB?

Hello,
I want to get execution plans of a query in a CLOB format. I am trying to run following query against v$sql view. One of the columns I want is the execution plan for the query. I am getting following error. Eventually, I am going to insert this data into a log table to keep history of all SQLs and their execution plans.
How can I do that?
Thank you in advance.
SQL> SELECT sql_id,
2         plan_hash_value,
3         TO_CLOB (DBMS_XPLAN.display_awr (sql_id            => sql_id,
4                                          plan_hash_value   => plan_hash_value,
5                                          format            => '+PEEKED_BINDS'))
6            sql_plan_clob,
7         buffer_gets,
8         executions
9    FROM v$sql
10   WHERE ROWNUM < 5;
       TO_CLOB (DBMS_XPLAN.display_awr (sql_id            => sql_id,
ERROR at line 3:
ORA-00932: inconsistent datatypes: expected NUMBER got SYS.DBMS_XPLAN_TYPE_TABLE

try first
select *
from table(DBMS_XPLAN.display_awr(sql_id          => sql_id,
                                    plan_hash_value => plan_hash_value,
                                    format          => '+PEEKED_BINDS'
            )to see the table returned
then try to adapt http://asktom.oracle.com/pls/apex/f?p=100:11:0::::P11_QUESTION_ID:68212348056 to produce fixed length rows.
look for describe_columns procedures in http://docs.oracle.com/cd/E11882_01/appdev.112/e25788/d_sql.htm#i1025449 for column length information available in internal tables and write the rows directly to clob instead of writing to disk and loading your clob from there.
Regards
Etbin
Edited by: Etbin on 31.10.2012 19:56
pointing to dbms_sql package added

How to show execution error message from a Process

hi
i have a requirement like to display the error messsage returned by the proceure.
I have a process with point After Submit and validations, where i am calling a procedure which returns the execution status with SUCCESS or FAILURE;
and if it FAILURE, it will return the error_message also, how can i show this message to the user just like how we are showing the process success message/validation message.
And i need to stop the process execution there itself once its got failed;
how can i achieve these two? anyone can give some inputs....
thanks in advance
renjish

paul and denes, thanks for the quick reply...
i tried the both option the message is coming properly. but the thing is i want to stop the execution there itself where i got the error from the procedure and the page should be remained in the same page.
currently i have a page 10(customer search screen), from there i called page 102 (customer edit screen) and in the page 102 i attached the process which includes the procedure to update the customer details;
Normally if update is success, the procedure will return SUCCESS and its navigating to the page 10(customer search screen.). so here if FAILURE is returning by procedure, i need to be in the same page i.e 102(customer edit) by showing the error message..just like a validation message...
currently whatever the procedure returns either SUCCESS or FAILURE, it goes to previous screen, but i need the method just like how the validation works if it fails.
hope you got....
regards
renjish

How to reduce execution time ?

Hi friends...
I have created a report to display vendor opening balances,
total debit ,total credit , total balance & closing balance for the given date range. it is working fine .But it takes more time to execute . How can I reduce execution time ?
Plz help me. It's a very urgent report...
The coding is as below.....
report yfiin_rep_vendordetail no standard page heading.
tables : bsik,bsak,lfb1,lfa1.
type-pools : slis .
--TABLE STRUCTURE--
types : begin of tt_bsik,
        bukrs type bukrs,
        lifnr type lifnr,
        budat type budat,
        augdt type augdt,
        dmbtr type dmbtr,
        wrbtr type wrbtr,
        shkzg type shkzg,
        hkont type hkont,
        bstat type bstat_d ,
        prctr type prctr,
        name1 type name1,
     end of tt_bsik,
     begin of tt_lfb1,
         lifnr type lifnr,
         mindk type mindk,
     end of tt_lfb1,
    begin of tt_lfa1,
        lifnr type lifnr,
        name1 type name1,
        ktokk type ktokk,
    end of tt_lfa1,
    begin of tt_opbal,
        bukrs type bukrs,
        lifnr type lifnr,
        gjahr type gjahr,
        belnr type belnr_d,
        budat type budat,
        bldat type bldat,
        waers type waers,
        dmbtr type dmbtr,
        wrbtr type wrbtr,
        shkzg type shkzg,
        blart type blart,
        monat type monat,
        hkont type hkont,
        bstat type bstat_d ,
        prctr type prctr,
        name1 type name1,
        tdr type dmbtr,
        tcr type dmbtr,
        tbal type dmbtr,
      end of tt_opbal,
     begin of tt_bs ,
        bukrs type bukrs,
        lifnr type lifnr,
        name1 type name1,
        prctr type prctr,
        tbal type dmbtr,
        bala type dmbtr,
        balb type dmbtr,
        balc type dmbtr,
        bald type dmbtr,
        bale type dmbtr,
        gbal type dmbtr,
    end of tt_bs.
************WORK AREA DECLARATION *********************
data : gs_bsik type tt_bsik,
        gs_bsak type tt_bsik,
        gs_lfb1 type tt_lfb1,
        gs_lfa1 type tt_lfa1,
        gs_ageing type tt_ageing,
        gs_bs type tt_bs,
        gs_opdisp type tt_bs,
        gs_final type tt_bsik,
        gs_opbal type tt_opbal,
        gs_opfinal type tt_opbal.
************INTERNAL TABLE DECLARATION*************
data : gt_bsik type standard table of tt_bsik,
        gt_bsak type standard table of tt_bsik,
        gt_lfb1 type standard table of tt_lfb1,
        gt_lfa1 type standard table of tt_lfa1,
        gt_ageing type standard table of tt_ageing,
        gt_bs type standard table of tt_bs,
        gt_opdisp type standard table of tt_bs,
        gt_final type standard table of tt_bsik,
        gt_opbal type standard table of tt_opbal,
        gt_opfinal type standard table of tt_opbal.
ALV DECLARATIONS *******************
data : gs_fcat type slis_fieldcat_alv ,
       gt_fcat type slis_t_fieldcat_alv ,
       gs_sort type slis_sortinfo_alv,
       gs_fcats type slis_fieldcat_alv ,
       gt_fcats type slis_t_fieldcat_alv.
**********global data declration***************
data :   kb type dmbtr ,
          return like bapireturn ,
          balancespgli like bapi3008-bal_sglind,
          noteditems like bapi3008-ntditms_rq,
          keybalance type table of bapi3008_3 with header line,
         opbalance type p.
SELECTION SCREEN DECLARATIONS *********************
selection-screen begin of block b1 with frame .
select-options : so_bukrs for bsik-bukrs obligatory,
                 so_lifnr for bsik-lifnr,
                 so_hkont for bsik-hkont,
                 so_prctr for bsik-prctr ,
                 so_mindk for lfb1-mindk,
                 so_ktokk for lfa1-ktokk.
selection-screen end of block b1.
selection-screen : begin of block b1 with frame.
parameters       : p_rb1 radiobutton group rad1 .
select-options   : so_date for sy-datum .
selection-screen : end of block b1.
********************************ASSIGNING ALV GRID
****field catalog for balance report
gs_fcats-col_pos = 1.
gs_fcats-fieldname = 'BUKRS'.
gs_fcats-seltext_m = text-001.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 2 .
gs_fcats-fieldname = 'LIFNR'.
gs_fcats-seltext_m = text-002.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 3.
gs_fcats-fieldname = 'NAME1'.
gs_fcats-seltext_m = text-003.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 4.
gs_fcats-fieldname = 'BALC'.
gs_fcats-seltext_m = text-016.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 5.
gs_fcats-fieldname = 'BALA'.
gs_fcats-seltext_m = text-012.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 6.
gs_fcats-fieldname = 'BALB'.
gs_fcats-seltext_m = text-013.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 7.
gs_fcats-fieldname = 'TBAL'.
gs_fcats-seltext_m = text-014.
append gs_fcats to gt_fcats .
gs_fcats-col_pos = 8.
gs_fcats-fieldname = 'GBAL'.
gs_fcats-seltext_m = text-015.
append gs_fcats to gt_fcats .
data : repid1 type sy-repid.
repid1 = sy-repid.
INITIALIZATION EVENTS ******************************
initialization.
*Clearing the work area.
clear gs_bsik.
Refreshing the internal tables.
refresh gt_bsik.
******************START OF SELECTION EVENTS **************************
start-of-selection.
*get data for balance report.
perform sub_openbal.
perform sub_openbal_display.
*&      Form sub_openbal
      text
--> p1        text
<-- p2        text
form sub_openbal .
if   so_date-low > sy-datum or so_date-high > sy-datum .
      message i005(yfi02).
     leave screen.
endif.
     select bukrs lifnr gjahr belnr budat bldat
       waers dmbtr wrbtr shkzg blart monat hkont prctr
       from bsik into table gt_opbal
       where bukrs in so_bukrs and lifnr in so_lifnr
       and hkont in so_hkont and prctr in so_prctr
       and budat in so_date .
    select bukrs lifnr gjahr belnr budat bldat
       waers dmbtr wrbtr shkzg blart monat hkont prctr
       from bsak appending table gt_opbal
       for all entries in gt_opbal
       where lifnr = gt_opbal-lifnr
       and budat in so_date .
if sy-subrc <> 0.
message i007(yfi02).
leave screen.
endif.
select lifnr mindk from lfb1 into table gt_lfb1
for all entries in gt_opbal
    where lifnr = gt_opbal-lifnr and mindk in so_mindk.
select lifnr name1 ktokk from lfa1 into table gt_lfa1
for all entries in gt_opbal
   where lifnr = gt_opbal-lifnr and ktokk in so_ktokk.
   loop at gt_opbal into gs_opbal .
     loop at gt_lfb1 into gs_lfb1 where lifnr = gs_opbal-lifnr.
       loop at gt_lfa1 into gs_lfa1 where lifnr = gs_opbal-lifnr.
        gs_opfinal-bukrs = gs_opbal-bukrs.
        gs_opfinal-lifnr = gs_opbal-lifnr.
        gs_opfinal-gjahr = gs_opbal-gjahr.
        gs_opfinal-belnr = gs_opbal-belnr.
        gs_opfinal-budat = gs_opbal-budat.
        gs_opfinal-bldat = gs_opbal-bldat.
        gs_opfinal-waers = gs_opbal-waers.
        gs_opfinal-dmbtr = gs_opbal-dmbtr.
        gs_opfinal-wrbtr = gs_opbal-wrbtr.
        gs_opfinal-shkzg = gs_opbal-shkzg.
        gs_opfinal-blart = gs_opbal-blart.
        gs_opfinal-monat = gs_opbal-monat.
        gs_opfinal-hkont = gs_opbal-hkont.
        gs_opfinal-prctr = gs_opbal-prctr.
        gs_opfinal-name1 = gs_lfa1-name1.
    if gs_opbal-shkzg    = 'H'.
        gs_opfinal-tcr   = gs_opbal-dmbtr * -1.
        gs_opfinal-tdr   = '000000'.
    else.
        gs_opfinal-tdr   = gs_opbal-dmbtr.
        gs_opfinal-tcr   = '000000'.
    endif.
       append gs_opfinal to gt_opfinal.
       endloop.
       endloop.
       endloop.
sort gt_opfinal by bukrs lifnr prctr .
so_date-low = so_date-low - 1 .
loop at gt_opfinal into gs_opfinal.
call function 'BAPI_AP_ACC_GETKEYDATEBALANCE'
exporting
    companycode        = gs_opfinal-bukrs
    vendor             = gs_opfinal-lifnr
    keydate            = so_date-low
   balancespgli        = ' '
   noteditems          = ' '
importing
    return             = return
tables
    keybalance         = keybalance.
clear kb .
loop at keybalance .
   kb = keybalance-lc_bal + kb .
endloop.
      gs_opdisp-balc = kb.
      gs_opdisp-bukrs = gs_opfinal-bukrs.
      gs_opdisp-lifnr = gs_opfinal-lifnr.
      gs_opdisp-name1 = gs_opfinal-name1.
    at new lifnr .
      sum .
      gs_opfinal-tbal = gs_opfinal-tdr + gs_opfinal-tcr .
      gs_opdisp-tbal = gs_opfinal-tbal.
      gs_opdisp-bala = gs_opfinal-tdr .
      gs_opdisp-balb = gs_opfinal-tcr .
      gs_opdisp-gbal = keybalance-lc_bal + gs_opfinal-tbal .
      append gs_opdisp to gt_opdisp.
    endat.
    clear gs_opdisp.
    clear keybalance .
endloop.
delete adjacent duplicates from gt_opdisp.
endform.                    " sub_openbal
*&      Form sub_openbal_display
      text
--> p1        text
<-- p2        text
form sub_openbal_display .
call function 'REUSE_ALV_GRID_DISPLAY'
    exporting
I_INTERFACE_CHECK                 = ' '
I_BYPASSING_BUFFER                = ' '
I_BUFFER_ACTIVE                   = ' '
      i_callback_program              = repid1
I_CALLBACK_PF_STATUS_SET          = ' '
I_CALLBACK_USER_COMMAND           = ' '
I_CALLBACK_TOP_OF_PAGE            = ' '
I_CALLBACK_HTML_TOP_OF_PAGE       = ' '
I_CALLBACK_HTML_END_OF_LIST       = ' '
I_STRUCTURE_NAME                  =
I_BACKGROUND_ID                   = ' '
I_GRID_TITLE                      =
I_GRID_SETTINGS                   =
IS_LAYOUT                         =
      it_fieldcat                     = gt_fcats
IT_EXCLUDING                      =
IT_SPECIAL_GROUPS                 =
IT_SORT                           =
IT_FILTER                         =
IS_SEL_HIDE                       =
I_DEFAULT                         = 'X'
I_SAVE                            = 'X'
IS_VARIANT                        =
   it_events                        =
IT_EVENT_EXIT                     =
IS_PRINT                          =
IS_REPREP_ID                      =
I_SCREEN_START_COLUMN             = 0
I_SCREEN_START_LINE               = 0
I_SCREEN_END_COLUMN               = 0
I_SCREEN_END_LINE                 = 0
IT_ALV_GRAPHICS                   =
IT_HYPERLINK                      =
IT_ADD_FIELDCAT                   =
IT_EXCEPT_QINFO                   =
I_HTML_HEIGHT_TOP                 =
I_HTML_HEIGHT_END                 =
IMPORTING
E_EXIT_CAUSED_BY_CALLER           =
ES_EXIT_CAUSED_BY_USER            =
     tables
       t_outtab                       = gt_opdisp
exceptions
    program_error                     = 1
    others                            = 2
if sy-subrc <> 0.
    message id sy-msgid type sy-msgty number sy-msgno
            with sy-msgv1 sy-msgv2 sy-msgv3 sy-msgv4.
endif.
endform.                    " sub_openbal_display

I think you are using for all entries statement in almost all select statements but i didnt see any condtion before you are using for all entries statement.
If you are using for all entries in gt_opbal ... make sure that gt_opbal has some records other wise it will try to read all records from the data base tables.
Try to check before using for all entries in the select statement like
if gt_opbal is not initial.
select adfda adfadf afdadf into table
for all entries in gt_opbal.
else.
select abdf afad into table
from abcd
where a = 1
    and b = 2.
endif.
i didnt see anything wrong in your report but this is major time consuming when you dont have records in the table which you are using for all entries.

Is this roughly how the labVIEW Execution Systems work?

I've not taken a class in OS design, so I don't know the strategies used to implement multitasking, preemptive or cooperative. The description below is a rough guess.
LabVIEW compiles Vis to execute within its own multitasking execution environment. This execution environment is composed of 6 execution systems. Each execution system has 5 priority queues (say priorities 0->4). Vis are compiled to one or more tasks which are posted for execution in these queues.
An execution system may either have multiple threads assigned to execute tasks from each priority queue, or may have a single thread executing all tasks from all priority queues. The thread priorities associated with a multithreaded execution system are assigned according to the queue that they service. There are therefore 5 available thread priority levels, one for each of the 5 priority level queues.
In addition to the execution queues, there are additional queues that are associated with tasks suspended in various wait states. (I don't know whether there are also threads associated with these queues. It seems there is.)
According to app. note 114, the default execution environment provides 1 execution system with 1 thread having a priority level of 1, and 5 execution systems with 10 prioritized threads, 2 threads per priority queue. NI has titled the single threaded execution system "user interface" and also given names to the other 5. Here they will be called either "user interface" or "other".
The "user interface" system is responsible for all GUI actions. It monitors the keyboard and mouse, as well as drawing the controls. It is also used to execute non-thread-safe tasks; tasks whose shared objects are not thread mutex protected.
Vis are composed of a front panel and diagram. The front panel provides an interface between the vi diagram, the user, and the calling vi. The diagram provides programmatic data flow between various nodes and is compiled into one or more machine coded tasks. In addition to it own tasks, a diagram may also call other vis. A vi that calls another vi does not actually programmatically branch to that vi. Rather, in most cases the call to another vi posts the tasks associated with the subvi to the back of one of the labVIEW execution system�s queues.
If a vi is non-reentrant, its tasks cannot run simultaneously on multiple threads. This implies a mutex like construction around the vi call to insure only one execution system is executing the vi. It doesn�t really matter where or how this happens, but somehow labVIEW has to protect an asynchronous vi from simultaneous execution, somehow that has to be performed without blocking an execution queue, and somehow a mutex suspended vi has to be returned to the execution queue when the mutex is freed. I assume this to be a strictly labVIEW mutex and does not involve the OS. If a vi is reentrant, it can be posted/ran multiple times simultaneously. If a vi is a subroutine, its task (I think there is always only one) will be posted to the front of the caller's queue rather than at the back of the queue (It actually probably never gets posted but is simply mutex tested at the call.) A reentrant-subroutine vi may be directly linked to its caller since it has no restrictions. (Whether in fact labVIEW does this, I don�t know. In any event, it would seem in general vis that can be identified as reentrant should be specified as such to avoid the overhead of mutexing. This would include vis that wrap reentrant dll calls.)
The execution queue to which a vi's tasks are posted depends upon the vi execution settings and the caller's execution priority. If the caller's execution priority is less than or equal the callee's execution settings, then the callee's tasks are posted to the back of the callee's specified execution queue. If the caller's execution priority is greater than the callee's specifications, then the callee's tasks are posted to the back of the caller's queue. Under most conditions, the vi execution setting is set to "same as caller" in which case the callee�s tasks are always posted to the back of the caller's execution queue. This applies to cases where two vis are set to run either in the other execution systems or two vis are set to run in the user interface execution system. (It�s not clear what happens when one vi is in the �user interface� system and the other is not. If the rule is followed by thread priority, any background tasks in the �other� systems will be moved to the user interface system. Normal task in the �other� systems called by a vi in the �user interface� system will execute in their own systems and vice versa. And �user interface� vis will execute in the caller�s �other� system if the caller has a priority greater than normal.)
Additionally, certain nodes must execute in the "user interface" execution system because their operations are not thread-safe. While the above generally specifies where a task will begin and end execution, a non-thread safe node can move a task to the �user interface� system. The task will continue to execute there until some unspecified event moves it back to its original execution system. Note, other task associated to the vi will be unaffected and will continue to execute in the original system.
Normally, tasks associated with a diagram run in one of the �other� execution systems. The tasks associated with drawing the front panel and monitoring user input always execute in the user interface execution system. Changes made by a diagram to it own front panel are buffered (the diagram has its own copy of the data, the front panel has its own copy of the data, and there seems to be some kind of exchange buffer that is mutexed), and the front panel update is posted as a task to the user interface execution system. Front panel objects also have the advanced option of being updated sequentially; presumably this means the diagram task that modifies the front panel will be moved to the user interface execution system as well. What this does to the data exchanged configuration between the front panel and diagram is unclear as presumably both the front panel and diagram are executing in the same thread and the mutex and buffer would seem to be redundant. While the above is true for a control value it is not clear whether this is also true for the control properties. Since a referenced property node can only occur on the local diagram, it is not clear it forces the local diagram to execute in the user interface system or whether they too are buffered and mutexed with the front panel.
If I were to hazard a guess, I would say that only the control values are buffered and mutexed. The control properties belong exclusively to the front panel and any changes made to them require execution in the �user interface� system. If diagram merely reads them, it probably doesn�t suffer a context switch.
Other vis can also modify the data structure defining the control appearance and values remotely using un-reference property nodes. These nodes are required to run in the user interface system because the operation is not thread-safe and apparently the diagram-front-panel mutex is specifically between the user interface execution system and the local diagram thread. Relative to the local diagram, remote changes by other vis would appear to be user entries.
It is not clear how front panels work with reentrant vis. Apparently every instance gets its own copy of the front panel values. If all front panel data structures were unique to an instance, and if I could get a vi reference to an instance of a reentrant vi, I could open multiple front panels, each displaying its own unique data. It might be handy, sort of like opening multiple Word documents, but I don�t think that it�s available.
A note: It is said that the front panel data is not loaded unless the front panel is opened. Obviously the attributes required to draw an object are not required, nor the buffer that interfaces with the user. This rule doesn�t apply though that if property references are made to front panel objects, and/or local variables are used. In those cases at least part of the front panel data has to be present. Furthermore, since all data is available via a control reference, if used, the control�s entire data structure must be present.
I use the vi server but haven�t really explored it yet, nor vi reference nodes, but obviously they too make modifications to unique data structures and hence are not thread-safe. And in general, any node that accesses a shared object is required to run in the user interface thread to protect the data associated with the object. LabVIEW, does not generally create OS level thread mutexes to protect objects probably because it becomes to cumbersome... Only a guess...
Considering the extra overhead of dealing with preemptive threading, I�m wondering if my well-tuned single threaded application in LV4.1 won�t out perform my well-tuned multithreaded application in LV6.0, given a single processor environment�
Please modify those parts that require it.
Thanks�
Kind Regards,
Eric

Ben,
There are two types of memory which would be of concern. There is temporary and persistent. Generally, if a reentrant vi has persistent memory requirements, then it is being used specifically to retain those values at every instance. More generally, reentrant code requires no persistent memory. It is passed all the information it needs to perform its function, and nothing is retained. For this type of reentrant vi, memory concern to which you refer could become important if the vis are using several MBytes of temporary storage for intermediate results. In that case, as you could have several copies executing at once, your temporary storage requirements have multiplied by the number of simultaneous copies executing. Your max memory use is going to rise, and as labview allocates memory rather independently and freely, the memory use of making them reentrant might be a bit of a surprise.
On the other hand, the whole idea of preemtive threading is to give those tasks which require execution in a timely fashion the ability to do so regardless of what other tasks might be doing. We are, after all, suffering the computational overhead of multithreading to accomplish this. If memory requirements are going to defeat the original objective, then we really are traversing a circle.
Anyway, as Greg has advised, threads are supposed to be used judiciously. It isn't as though your going to have all 51 threads up at the same time. In general I think, overall coding stategy should be to minimize the number of threads while protecting those tasks that absolutely require timely execution.
In that sense, it would have been nice if NI had retained two single threaded systems, one for the GUI and one for the GUI interface diagrams. I've noticed that control drawing is somewhat slower under LV6.0 than LV4.1. I cannot, for example, make a spreadsheet scroll smoothly anymore, even using buffered graphics. This makes me wonder how many of my open front panel diagrams are actually running on the GUI thread.
And, I wonder if threads go to sleep when not in use, for example, on a wait, or wait multiple node. My high priority thread doesn't do a lot of work, but the work that it does is critical. I don't know what it's doing the rest of the time. From some of Greg's comments, my impression is it in some kind of idle mode: waking up and sleeping, waking up and sleeping,..., waking up, doing something and sleeping... etc. I suppose I should try to test this.
Anyway that's all an aside...
With regard to memory, your right, there are no free lunches... Thanks for reminding me. If I try this, I might be dismayed by the additional memory use, but I won't be shocked.
Kind Regards,
Eric

How prevent simultaneous execution of multiple button threads?

My AS 3 program has multiple buttons. Users can select one and then immediately select another and this causes 2 threads that collide. Once one button is executing, I want the other buttons to ignore clicks.
I've tried using a lock:Boolean to indicate a button is being processed. Each button checks lock. My logic is such that when the AS 3 processor detects a locked condition, it abandons execution of that button. However, surprisingly, it abandons execution only termporarily ... once the the boolean is unlocked, AS 3 comes back and executes the button.
The problems are twofold: 1) the first time the 2nd button attempts to execute (by checking lock), when it returns (from checking lock) and attempts to pick up processing where it left off, it seems to forget where it was and does not utlimately complete its task(s); possibly variables have been altered, it is difficult to say. That is, AS 3 is unable to successfully pickup where it left off on the first button.
2) the second problem is that AS 3 incorrectly returns to button 2 after the lock condition is cleared. It persists and will execute that button.
Can anyone tell me how once one button is selected, the others can be locked out and won't execute?? Multiple threads from these buttons is a problem.
Thanks in advance.
Steve @ U Iowa

dmennenoh - OK. The downside to that type of solution is that each button has to "know" which other buttons are on the stage at that time, but, yes, that should work. Do you think turning their visibility off would or would not be as effective as removing the event listeners? I'm thinking turning visiblity on or off is simpler and simpler to manage. Thanks for your help.

How to delay execution?

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