[logback-dev] synchronization style?

[Maarten Bosteels]

I agree with Ralph: try to keep the locks as briefly as possible.
Because
a) it could improve scalability
b) the reason that Joern gives
c) if there ever is a need to change it, making synchonized blocks bigger is
probably easier than trying to make them smaller

I definitely agree about not penalizing *all* users with fair locks.

from Java Concurrency In Practice:

"While shrinking synchronized blocks can improve scalability, a
synchronizedblock can be
too small. - operations that need to be atomic (such updating multiple
variables that participate in an invariant) must be contained in a single
synchronized block. And because the cost of synchronization is nonzero,
breaking one synchronized block into multiple synchronized blocks
(correctness permitting) at some point becomes counterproductive in terms of
performance.[9]<http://book.javanb.com/java-concurrency-in-Practice/ch11lev1sec4.html#ch11fn09>The
ideal balance is of course platform-dependent, but in practice it
makes
sense to worry about the size of a synchronized block only when you can move
"substantial" computation or blocking operations out of it.

[9] If the JVM performs lock coarsening, it may undo the splitting of
synchronized blocks anyway."

http://book.javanb.com/java-concurrency-in-Practice/ch11lev1sec4.html

Maarten



On Thu, Jul 2, 2009 at 4:37 PM, Ceki Gulcu <ceki at qos.ch> wrote:

>
>
> Ralph Goers wrote:
>
>> I would recommend the second, largely because some of the things that are
>> being synchronized might be able to be converted to constructs that don't
>> require synchronization. Furthermore, as long as you are holding a lock over
>> such a wide scope you run the risk of something being inserted into that
>> synchronized block that does something that raises the possibility of a
>> deadlock.
>>
>
> Agreed.
>
>  I would comment more but my wife is in the hospital for the next few days
>> so I won't have much time until after the weekend.
>>
>
> My best wishes to your wife.
>
>  Ralph
>>
> --
> Ceki Gülcü
> Logback: The reliable, generic, fast and flexible logging framework for
> Java.
> http://logback.qos.ch
> _______________________________________________
> logback-dev mailing list
> logback-dev at qos.ch
> http://qos.ch/mailman/listinfo/logback-dev
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://qos.ch/pipermail/logback-dev/attachments/20090702/cd9943a9/attachment.htm>