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Cleanup #453

Remove unused data members from classes and structs used in the RTS

Added by Lukasz Wesolowski over 5 years ago. Updated over 2 years ago.

Status:
New
Priority:
Normal
Assignee:
PPL
Category:
-
Target version:
-
Start date:
03/29/2014
Due date:
% Done:

0%


Description

I recently found an unused data member (char gName256) in the TableEntry class. TableEntry is used to store group information in the Charm++ _groupTable. Apart from the unused variable, TableEntry has only a few other data members, so gName is responsible for most of the size of TableEntry objects. As _groupTable is essentially a hash table, I wondered whether the empty space is adversely affecting performance when doing searches on the hash table. I ran a test of EpiSimdemics with gName commented out, and performance did improve by about 1%.

Keeping the RTS footprint small and tidy is clearly beneficial for performance and readability. We should eliminate unused variables from anywhere inside the repository, but especially from classes and structs used to hold frequently accessed data.

The task is to:
(1) identify frequently accessed data structures in the RTS
(2) grep for the name of each data member in the corresponding classes
(3) remove unused data members and test performance

History

#1 Updated by Probir Roy over 3 years ago

  • Assignee set to Probir Roy

#2 Updated by Laxmikant "Sanjay" Kale over 3 years ago

We need to make sure the extra fields are not added for cache alignment. This is rare, and only happens in message envelopes etc. But for this reason, you should get this reviewed by a senior member (e.g. Phil, Nikhil, ..). Hopefully, the fieldname will tell you if this is so.

#3 Updated by Sam White over 2 years ago

  • Assignee changed from Probir Roy to PPL

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