Btw. you may find the X10 language specification useful as well
http://x10.sourceforge.net/documentation/languagespec/x10-230.pdf
Thanks,
Saliya
On Fri, Nov 16, 2012 at 11:45 AM, Saliya Ekanayake <esal...@gmail.com>wrote:
> Thank you, I see what you meant now.
>
> Yes, it seems all atomic operations in one place is handled with an
> exclusive lock. So as a workaround will something like this work,
>
> In your class having a boolean variable, say *inUse *which is initially *
> false*. Then you will implement your method without specifying as an
> atomic method, say *m( )*
> *
> *
> Now having an entry and exit atomic sections like,
>
> when (! inUse) {
> inUse = true;
> }
>
> m( ); // the time consuming operation
> inUse = false;
>
> Thank you,
> Saliya
>
>
>
>
>
>
> On Fri, Nov 16, 2012 at 10:59 AM, LEONID ILYEVSKY <
> leonidilyev...@yahoo.com> wrote:
>
>> Saliya,
>>
>> Thanks for your reply.
>> Let me clarify my question. This situation, I believe, is pretty common
>> actually.
>>
>> So I have multiple objects of the same class. The methods are made
>> synchronized because they update the objects' data based on the previous
>> values and some information read from, let say, files or database. Such
>> operation may take some time, and it is important that two different
>> instances may be processed in parallel.
>> On the other hand, if two threads try to update the same object, then
>> only one at a time can be allowed, the other thread(s) must wait.
>> So, in Java this is achieved simply by declaring methods synchronized,
>> and then I safely can have a pool of threads doing the work, efficiently
>> utilizing resources, and be sure that no data corruption happens.
>>
>> I am reading now http://www.cs.rice.edu/~vs3/PDF/pmup06.pdf , and it
>> says that currently atomic behavior is implemented by an exclusive lock on
>> the place. This means that parallel operation as described in my java
>> example will be impossible in X10. I understand that this approach helps to
>> make sure that deadlock never happens.
>>
>> However, real life applications may require more parallelizm. For
>> example, the classical textbook banking application. I withdraw my money
>> from the ATM, at the same time the back office application is trying to
>> apply direct deposit to my account. These operations must be syncronized,
>> but operations on othe client's accounts can be applied at the same time,
>> they don't have to wait.
>>
>>
>>
>> ------------------------------
>> *From:* Saliya Ekanayake <esal...@gmail.com>
>> *To:* LEONID ILYEVSKY <leonidilyev...@yahoo.com>; Mailing list for users
>> of the X10 programming language <x10-users@lists.sourceforge.net>
>> *Sent:* Friday, November 16, 2012 10:38 AM
>> *Subject:* Re: [X10-users] Atomic blocks
>>
>> Hi Leonid,
>>
>> In your java version, are the threads accessing a separate copy of your
>> object? If so it seems like it should work even without being a
>> synchronized method. Also, if you create multiple objects and access them
>> from separate activities in X10 they should not block and atomic may not
>> make any difference as I understand.
>>
>> In fact, atomic usage is beneficial only when you have a critical section
>> that at a given time only one activity is allowed to be in (per place).
>>
>> Hope this helps.
>>
>> Thank you,
>> Saliya
>>
>>
>> On Fri, Nov 16, 2012 at 10:28 AM, LEONID ILYEVSKY <
>> leonidilyev...@yahoo.com> wrote:
>>
>> Hi,
>>
>> I am new to X10, and I have a question about the atomic construct, maybe
>> somebody can clarify it for me.
>>
>> Let say, in Java I have a class with some synchronized (on the object
>> level) methods. If I have 100 such objects in memory, then 100 threads can
>> simultaneously work on those objects without blocking each other.
>> How you do the same thing in X10 (asuming the program is running in one
>> place)? From the definition of the atomic block, it seems that if I
>> translate Java syncronized methods to X10 atomic methods, then only one
>> object at a time can be processed. Is my understanding correct?
>>
>>
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>>
>>
>> --
>> Saliya Ekanayake
>> http://www.esaliya.blogspot.com
>> http://www.esaliya.wordpress.com
>>
>>
>>
>
>
> --
> Saliya Ekanayake
> http://www.esaliya.blogspot.com
> http://www.esaliya.wordpress.com
>
--
Saliya Ekanayake
http://www.esaliya.blogspot.com
http://www.esaliya.wordpress.com
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