[eclipse-clp-users] Is referenced_record/2 related to accessing asserted clauses?

From: Edwin Wirawan <edcsgt_at_...32...>
Date: Fri, 23 Nov 2012 16:31:39 +0800

I tried profiling a run of my code and the result showed that the majority of the time (~80%) is spent in referenced_record/2.

My code asserts a lot of dynamic clauses at runtime and refers to these dynamic clauses regularly.

Does referenced_record/2 spend most of its runtime accessing asserted clauses, or doing something else?

FYI, each asserted clause is of the form: edge(edgeN,
...more content...), where edgeN is unique for each asserted edge clause (e.g., edge1, edge2,edge3,бн).

~200K such clauses are asserted during a typical run.

A slightly related question: I also called statistics/1. There were 
200K+ dictionary_entries, dict_hash_usage showed that the dictionary was
 full (8192/8192) and the dict_has_collisions had a value of 

My guess is that the majority of 200K+ dictionary entries correspond to
 our asserted 'edge' clauses, which leads me to wonder if the large 
number of dictionary collisions means that the dictionary is using the 
functor 'edge' or some other conflicted
 value as a key instead of my unique edge ID values. Does that seem 
right? Would the dictionary hash function have any difficulty 
distinguishing IDs that share a common substring such as 'edge', and 
thus cause the seemingly high number of collisions?

Finally, assuming the time spent in referenced_record/2 is spent on 
accessing asserted clauses, could that long time be somehow related to 
the large number of collisions in the dictionary? Could it be that the 
same keys are used for hashing both in the dictionary
 and the database of asserted clauses?
 This would mean that the large number of collisions in the dictionary 
would imply that there is also a large number of collisions in the 
database of asserted
 clauses, thus slowing down access to asserted clauses and resulting in 
referenced_record/2 taking a large chunk of the total time spent.

I am also wondering whether there is a way to inspect the structure and 
content of the dictionary and the database of asserted clauses, and also
 whether there's a memory profiler for ECLiPSe.


Received on Fri Nov 23 2012 - 08:31:50 CET

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