Changes between Version 12 and Version 13 of user_synchro


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Timestamp:
Oct 10, 2018, 11:31:31 AM (3 years ago)
Author:
alain
Comment:

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  • user_synchro

    v12 v13  
    5656
    5757For each user barrier, ALMOS-MKH creates a kernel ''remote_barrier_t'' structure, dynamically allocated in the reference cluster (i.e. in the cluster containing the reference process descriptor).
    58  * The '''remote_barrier_create()''' function allocates and initializes a barrier, using an RPC if if the calling thread is not running in the reference cluster.
     58 * The '''remote_barrier_create()''' function allocates and initializes a barrier, to define the number of expected threads, using an RPC if if the calling thread is not running in the reference cluster.
    5959 * The '''remote_barrier_destroy()''' function destroys a given barrier, using RPC if the calling thread is not running in the reference cluster.
    60  * The blocking '''remote_barrier_wait()''' function returns only when all expected threads (defined by the remote_barrier_create() function) reach the barrier. It implement a descheduling policy: when a thread is not the last expected thread, it register in he barrier waiting queue and blocks on the THREAD_BLOCKED_USERSYNC condition. The last thread reset the barrier and unblocks all waiting threads.
     60 * The blocking '''remote_barrier_wait()''' function returns only when all expected threads reach the barrier. It implements a descheduling policy: when a thread is not the last expected thread, it register in he barrier waiting queue and blocks on the THREAD_BLOCKED_USERSYNC condition. The last thread reset the barrier and unblocks all waiting threads.
     61
     62N.B. ''In the current implementation, the barrier is physically implemented in the reference cluster, creating contention when the
     63number of threads is large. It exists a distributed implementation, where the barrier is implemented as a quad-tree, entirely  in user space (no system calls)''.
    6164
    6265== E) Semaphore ==