work-force.cpp

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/*
  WorkForce.hpp  -  actively coordinated pool of workers for rendering

  Copyright (C)         Lumiera.org
    2023,               Hermann Vosseler <Ichthyostega@web.de>

  This program is free software; you can redistribute it and/or
  modify it under the terms of the GNU General Public License as
  published by the Free Software Foundation; either version 2 of
  the License, or (at your option) any later version.

  This program is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program; if not, write to the Free Software
  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.

* *****************************************************/

#include "vault/gear/work-force.hpp"
#include "lib/util.hpp"


namespace vault{
namespace gear {
  
  namespace { // internal details
    
    size_t MINIMAL_CONCURRENCY = 2;
    
  } // internal details
  
  
  
  size_t work::Config::COMPUTATION_CAPACITY = Config::getDefaultComputationCapacity();
  
  size_t
  work::Config::getDefaultComputationCapacity()
  {
    return util::max (std::thread::hardware_concurrency()
                     , MINIMAL_CONCURRENCY);
  }
  
  
  void
  work::performRandomisedSpin (size_t stepping, size_t randFact)
  {
    size_t degree = CONTEND_SOFT_FACTOR * (1+randFact) * stepping;
    for (volatile size_t i=0; i<degree; ++i) {/*SPIN*/}
  }
  
  microseconds
  work::steppedRandDelay (size_t stepping, size_t randFact)
  {
    REQUIRE (stepping > 0);
    uint factor = 1u << (stepping-1);
    return (CONTEND_WAIT + 10us*randFact) * factor;
  }


}} // namespace vault::gear