Changes between Version 35 and Version 36 of processus_thread

Timestamp:

Nov 6, 2017, 3:39:33 PM (7 years ago)

Author:

alain

Comment:

--

processus_thread

@@ -72 +72 @@
 The process creation in a remote cluster implement the POSIX fork() / exec()  mechanism.
 When a parent process P executes the fork() system call, a new child process C is created.
-The new C process inherit from the parent process P the open files (FDT), and the memory image (VSL and GPT). These structures must be replicated in the new process descriptor. After a fork(), the C process can execute an exec() system call, that allocate a new memory image to the C process, but the new process can also continue to execute with the inherited memory image. For load balancing, ALMOS-MKH  uses the DQDT to create the child process C on a different cluster from the parent cluster P, but the user application can also use the fork_place() system call to specify the target cluster.
+The new C process inherit from the parent process P the open files (FDT), and the memory image (VSL and GPT). These structures must be replicated in the new process descriptor. After a fork(), the C process can execute an exec() system call, that allocate a new memory image to the C process, but the new process can also continue to execute with the inherited memory image. For load balancing, ALMOS-MKH  uses the DQDT to create the child process C on a different cluster from the parent cluster P, but the user application can also use the non-standard fork_place() system call to specify the target cluster.
 
 === 3.1) fork() ===
 
-The parent process P is running on a core in cluster K, and executes the fork() system call to create a new process C on a remote cluster Z, that will  become the owner of the C process. ALMOS-MK creates the first C process descriptor in the same cluster as the parent cluster P, and postpone the costly remote copy of VSL and GPT from P to C, because this copy is useless in case of exec(). When the fork() system call returns, the C process owner cluster is Z, but the reference process descriptor is in cluster K. The child process and the associated main thread will be migrated to cluster Z later, when the child process makes an "exec" or any other system call. 
+FIRST SPECIFICATION:
+
+A thread of parent process P, running in a cluster K,  executes the fork() system call to create a new process C on a remote cluster Z, that will  become the owner for the C process. ALMOS-MK creates the first C process descriptor in the same cluster as the parent cluster P, and postpone the costly remote copy of VSL and GPT from P to C, because this copy is useless in case of exec(). When the fork() system call returns, the C process owner cluster is Z, but the reference process descriptor is in cluster K. The child process and the associated main thread will be migrated to cluster Z later, when the child process makes an "exec" or any other system call. 
 
  1. the cluster K allocates memory in K for the reference process descriptor of C, and get a pointer on this process descriptor.
@@ -85 +87 @@
 
 At the end of the fork(), the owner cluster for the new  C process is cluster Z, and the reference cluster is cluster K. This C process contains one single thread running on K.
+
+SECOND SPECIFICATION
+
+A thread of parent process P, running in a cluster X,  executes the fork() system call to create a child process C on a remote cluster Y, that will  become both the owner and the reference cluster for the C process. If the reference cluster Z for process P is different from X, the work must be done in  cluster Z, because only the reference cluster Z contains a complete description of the parent process VSL and GPT. 
 
 === 3.2) exec() ===