[jira] [Created] (DISPATCH-479) Use atomic operations for ref counts

["Ulf Lilleengen (JIRA)" <ji...@apache.org>]

Ulf Lilleengen created DISPATCH-479:
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             Summary: Use atomic operations for ref counts
                 Key: DISPATCH-479
                 URL: https://issues.apache.org/jira/browse/DISPATCH-479
             Project: Qpid Dispatch
          Issue Type: Bug
            Reporter: Ulf Lilleengen
            Priority: Minor


I ran some profiling using perf, and on the test server hardware, the locking related to ref counts on delivery and message was most contended. The benchmark is basically send unsettled messages as fast as it can.

I'm seeing ~10% improvement in throughput with this patch on the test server at least, but there was no noticable improvement on my laptop. It might be that the cost of locking is much less on newer hardware. [~mwagner] It would be great if you could test the patch to see if it has any effect for your tests.

Another question is if/how to use atomic instructions in dispatch. If  c11 is preferred, I can change to that, but it appears it is not available for older RHEL versions, so the patch uses GCC extensions.



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