Re^4: Is it possible to create a single Hash-of-Hash.. with multiple threads..

[gsat]

Dear Monk BrowserUk! Please take a bow!!

Thank You so much - for enlightening me :) Indeed - it was my lack of understanding.

I have found this entire discussion from everybody - very helpful.

-=-=-=-=-=-=-=-

Now, I need more :) It seems - me and my code is tired of doing so many .. if exists.. else share.. kinda additives before I do any structure change - and I think no way to avoid that. Now a couple of Questions here:

Q1. Is there any easier method?

Q2. Is it possible to grow a local tree or branch data-structure, then create a shared_clone - and graft the new tree to s sub-branch of main shared tree?

Q3. I have few subroutines to be called many times - based on data - from inside my thread_worker. So far I am lacking depth in understanding or visualizing - how/when multiple threads work on different set of data, while calling a subroutine - does the code-inside-subroutine-block gets a replicated inside the thread uniquely? - else how the sanity is retained? - sorry if I am asking too basic question - maybe it is the case, I am confused - and not clear enough - where is my confusion too..

Q4. Inside subroutine - do I have to use every variable as local and not-shared?

Thanks a lot! Again & Again!

[BrowserUk]

1. No.

   You can replace:

               if( exists $copyRef->{ $step } ) {
                    $copyRef = $copyRef->{ $step };
                }
                else {
                    lock %{ $copyRef };
                    $copyRef = $copyRef->{ $step } = &share( {} );
                }
   

   With:

               lock %{ $copyRef };
               $copyRef = $copyRef->{ $step } //= &share( {} )
   

   Which is more compact, but not easier nor more efficient.

2. Yes.

   Two possibilities:

   1. You can build a normal (non-shared) subhash and when complete, use threads::shared::shared_clone() to make a shared copy of it and assign a reference to the copy to a key/value pair in the main shared hash:

      ...
      my %subhash;
      ... # populate it
      lock %mainSharedHash;
      $mainSharedHash{ $key } = shared_clone( \%subhash );
      ...
      

   2. You can create a shared subhash and assign a ref to it without needing to copy:

      ...
      my %subhash :shared:
      ... # populate it
      lock %mainSharedHash;
      $mainSharedHash{ $key } = \%subhash;
      

3. I do not understand the question.

   You'll get better answers if you describe your actual application. Ie. Real requirements garner working responses.

4. Again, your question makes no sense.

   In a subroutine (or anywhere else), you can use unshared variables and/or shared variables as required.