progress_assurance.h

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/*
The MIT License (MIT)

Copyright (c) 2015 University of Central Florida's Computer Software Engineering
Scalable & Secure Systems (CSE - S3) Lab

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#ifndef TERVEL_UTIL_PROGRESS_ASSURANCE_H_
#define TERVEL_UTIL_PROGRESS_ASSURANCE_H_

#include <atomic>
#include <memory>
#include <assert.h>
#include <tervel/util/info.h>
#include <tervel/util/util.h>
#include <tervel/util/memory/hp/hp_element.h>


namespace tervel {
namespace util {

namespace memory {
namespace hp {
  class Element;
}
}

class OpRecord : public memory::hp::Element {
 public:
  OpRecord() {}

  virtual void help_complete() = 0;

  using memory::hp::Element::on_watch;
  bool on_watch(std::atomic<void *> *address, void *expected) {
    return true;
  }

  using memory::hp::Element::on_is_watched;
  bool on_is_watched() {return false;}
  using memory::hp::Element::on_unwatch;
  void on_unwatch() {}


 private:
  DISALLOW_COPY_AND_ASSIGN(OpRecord);
};


class ProgressAssurance {
 public:
  //static constexpr size_t MAX_FAILURES = TERVEL_PROG_ASSUR_LIMIT;

  static constexpr size_t HELP_DELAY = TERVEL_PROG_ASSUR_DELAY;


  class Limit {
   public:
    explicit Limit(size_t limit = TERVEL_PROG_ASSUR_LIMIT)
      : counter_(limit) {}

    bool isDelayed(size_t val = 1) {
      size_t temp = counter_;
      counter_ -= val;
      return (temp == 0);
    }

    void reset(size_t limit = TERVEL_PROG_ASSUR_LIMIT) {
      counter_ = limit;
    }
   private:
    size_t counter_;
  };

  explicit ProgressAssurance(size_t num_threads)
      : op_table_(new std::atomic<OpRecord *>[num_threads]() )
      , num_threads_ {num_threads} {}

  static void check_for_announcement(ProgressAssurance * const progress_assuarance =
        nullptr) {
    static __thread size_t delay_count = HELP_DELAY;
    static __thread size_t help_id = 0;

    if (delay_count-- == 0) {
      delay_count = HELP_DELAY;
      if (progress_assuarance ==  nullptr) {
        tervel::tl_thread_info->get_progress_assurance()->
          p_check_for_announcement(help_id);
      } else {
        progress_assuarance->p_check_for_announcement(help_id);
      }
    }
  }

  static void make_announcement(OpRecord *op, const uint64_t tid =
        tervel::tl_thread_info->get_thread_id(), ProgressAssurance * const prog_assur =
        tervel::tl_thread_info->get_progress_assurance()) {
    prog_assur->p_make_announcement(op, tid);
  }

 private:
  void p_check_for_announcement(size_t &hpos);

  void p_make_announcement(OpRecord *op, const uint64_t tid =
        tervel::tl_thread_info->get_thread_id());

  std::unique_ptr<std::atomic<OpRecord *>[]> op_table_;

  const size_t num_threads_;

  DISALLOW_COPY_AND_ASSIGN(ProgressAssurance);
};

}  // namespace util
}  // namespace tervel

#endif  // TERVEL_UTIL_PROGRESS_ASSURANCE_H_