mirrors/eiffel-org
1
0
Fork 0
mirror of https://github.com/EiffelSoftware/eiffel-org.git synced 2025-12-07 15:22:31 +01:00
Code Issues Packages Projects Releases Wiki Activity

Author:halw

Browse Source 
Date:2011-05-23T12:32:22.000000Z


git-svn-id: https://svn.eiffel.com/eiffel-org/trunk@911 abb3cda0-5349-4a8f-a601-0c33ac3a8c38
This commit is contained in:
halw
2011-05-24 20:15:48 +00:00
parent e07189d1b6
commit 6d56a366f3
1 changed files with 7 additions and 1 deletions
Download Patch File Download Diff File Expand all files Collapse all files

8
documentation/current/solutions/concurrent-computing/concurrent-eiffel-scoop/scoop-implementation.wiki
View File

@@ -8,11 +8,17 @@ The implementation of SCOOP within EiffelStudio varies from the definition as it
Some of the differences stem from the reality that SCOOP systems could be optimized for performance, including maximizing concurrency. For example, even though the SCOOP rules state that a separate call to a query is synchronous, i. e., the calling processor waits until the query completes before proceeding, if a static analysis can show that the wait is not necessary to the proper functioning of the remainder of the calling routine, then the call to the query can be done asynchronously. Some of the differences stem from the reality that SCOOP systems could be optimized for performance, including maximizing concurrency. For example, even though the SCOOP rules state that a separate call to a query is synchronous, i. e., the calling processor waits until the query completes before proceeding, if a static analysis can show that the wait is not necessary to the proper functioning of the remainder of the calling routine, then the call to the query can be done asynchronously.
In other ways, particularly for early versions, the EiffelStudio implementation may not cover all the goals of SCOOP as declared in the various publications. Certain elements that are defined in the SCOOP descriptions may not yet be present, or only partially implemented in the EiffelStudio implementation. In other ways, particularly for early versions, the EiffelStudio implementation may not cover all the goals of SCOOP as stated in the various publications. Certain elements that are defined in the SCOOP descriptions may not yet be present, or only partially implemented in the EiffelStudio implementation.
The differences between the EiffelStudio implementation of SCOOP and current and previous definitions of the SCOOP model are shown below. The differences between the EiffelStudio implementation of SCOOP and current and previous definitions of the SCOOP model are shown below.
=The Wait Rule=
The [[Concurrent Eiffel with SCOOP#Access to shared resources|Wait Rule]] says: ''A routine call with separate arguments will execute when all corresponding processors are available and hold them exclusively for the duration of the routine.''
In the EiffelStudio implementation, a routine will not necessarily wait for all processors associated with its separate arguments to be available before it ''begins'' execution. The waiting on processors occurs in a "lazy" manner. Execution will only wait on the availability of one of the processors when it actually needs to use the argument associated with that processor. This means that if there are several instructions ahead of the first instruction that references a separate argument, then those several instructions will be executed immediately. Only at the point at which the separate argument's processor was needed would the routine pause and wait for the availability of the processor.