Re: A question about synchronized threads
On 29.04.2011 18:12, byhesed wrote:
On 4=EC=9B=9430=EC=9D=BC, =EC=98=A4=EC =8412=EC=8B=9C53=EB=B6=84, Lew=
<no...@lewscanon.com> wrote:
What do you mean by "better"? What precisely is not the way you want =
it?
What is your standard of effectuality?
If too much spaces are marked as critical regions,
then the program will not be optimized.
It wastes too much time in waiting for obtaining a right to access
critical regions.
So, in my question, better means optimization when using threads.
There is no one size fits all answer to that question. It completely
depends on the nature of your application. For example, if read
accesses vastly outnumber write accesses you will get significant
improvements by using read write locks. If it is the other way round
you won't notice a big difference between using "synchronized" and a
read write lock (because most of the time the exclusive write lock will
be used).
In other situations not sharing mutable state (i.e. copying mutable
state or using immutable state) might be the best solution. Or you use
a thread safe data structure such as copy on write list.
There is a whole, big toolbox for writing scalable thread safe
applications. Eric has it exactly right with his suggestion because the =
nature of the state (shared, not shared, mutable, immutable) is the
important aspect to reason about. I recommend reading Doug Lea's
excellent book on the matter.
Kind regards
robert
--
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