Reducing the work during a coarse lock.

[whitingjr]

Hi,

Both I and members in my team are interested to know what can be moved outside of a coarse synchronized block in the IJ codebase. It is in the returnConnection method for a managed connection pool. We are seeing a high amount of time spent blocked on the cls object.

ironjacamar/core/src/main/java/org/jboss/jca/core/connectionmanager/pool/mcp/SemaphoreArrayListManagedConnectionPool.jav…

There are a number of things that we would like to move outside the synchronized block. Here is a list of suggestions (not all my own):

1. checking the state of the connection listener and the outcome deturmining the state of the variable 'kill'. line 446-447
2. wrap the call to statistics.setInUsedCount with an if statement checking whether statistics is true. It is known that a call to statistics.setInUsedCount contains inside it the same check but, by then 3 method calls have been made. Whereas only 1 needs calling using the wrapping. It's not much but everything counts in this large block of code. L450
3. move the modification of the two permits references, L 483-487
4. move the call to used(), L 472

and this simple optimization:

1. remove the check for the key in the collection, instead try removing the object and checking the method return value. If not null then release the permit. L 483-487

For each mentioned relocation of code, how much is necessary for the code to remain correct ?

Jeremy

[jesper.pedersen]

checking the state of the connection listener and the outcome deturmining the state of the variable 'kill'. line 446-447

Yeah, that can be moved outside.

wrap the call to statistics.setInUsedCount with an if statement checking whether statistics is true. It is known that a call to statistics.setInUsedCount contains inside it the same check but, by then 3 method calls have been made. Whereas only 1 needs calling using the wrapping. It's not much but everything counts in this large block of code. L450

Yeah, and it can be moved outside.

move the modification of the two permits references, L 483-487

Yeah, modifying the permit outside of the block is ok.

move the call to used(), L 472

Nope, that needs to happen due to the XAResource timeout reset.

remove the check for the key in the collection, instead try removing the object and checking the method return value. If not null then release the permit. L 483-487

Yeah.

[jesper.pedersen]

The changes has been merged.