Changes between Version 21 and Version 22 of AppMultiThread


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Timestamp:
Dec 30, 2008, 3:31:43 PM (16 years ago)
Author:
davea
Comment:

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  • AppMultiThread

    v21 v22  
    1313 * You want to reduce the turnaround time of your jobs (either because of human factors, or to reduce server occupancy).
    1414
    15 Writing and debugging a multi-threaded app is hard.
    16 You may be able to use languages like Titanium or Cilk,
    17 or libraries of multi-threaded numerical "kernels".
     15You may be able to use CUDA, or languages like Titanium or Cilk,
     16or libraries of multi-threaded numerical "kernels", to develop a multi-threaded app.
    1817
    1918== Deploying a multi-threaded app version ==
     
    3130{{{
    3231bool app_plan(SCHEDULER_REQUEST& sreq, const char* plan_class, HOST_USAGE& hu) {
    33     // clients before 6.1.11 don't understand plan_class
    34     //
    35     int v = sreq.core_client_major_version*10000
    36         + sreq.core_client_minor_version*100
    37         + sreq.core_client_release;
    38     if (v < 60111) return false;
    39 
    4032    if (!strcmp(plan_class, "par64")) {
    4133        int ncpus, nthreads;
     
    5547}
    5648}}}
    57 
    58 == Client scheduling policy ==
    59 
    60 Suppose an app A uses NT(A) threads.
    61 Ideally, on a host with N CPUs, we want
    62 NT(A), summed over running apps, to be at least N;
    63 otherwise CPU time is wasted.
    64 However, if it's much more than N,
    65 we increase latency without increasing throughput,
    66 we may increase synchronization overhead,
    67 and we may use more RAM than needed.
    68 
    69 Given a list of runnable applications (ordered by priority or deadline),
    70 the CPU scheduler runs applications until the number of threads reaches a limit.
    71 If the user has specified a limit N on the number of CPUs to use,
    72 the number of threads cannot exceed N.
    73 Otherwise, the scheduler stop when the number of threads is >= NCPUS.
    74