MallocOpts.h

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#ifndef art_Utilities_MallocOpts_h
#define art_Utilities_MallocOpts_h

// -*- C++ -*-
//
// Package:     Utilities
// Class  :     MallocOpts
//
// Original Author:  Jim Kowalkowski
//
//
// ------------------ malloc option setter -----------------------
//
// There is a global instance of MallocOptionSetter.  Upon construction,
// it gets the CPU type.  If is it AMD or Intel, it sets the mallopt
// parameters to a set that works best for that environment.  The best
// values have been chosen based on running a simple fw job.
//
// The four values that get reset are:
//   M_MMAP_MAX, M_TRIM_THRESHOLD, M_TOP_PAD, M_MMAP_THRESHOLD
//
// Current the best AMD and Intel values were calculated using:
//   AMD Opteron(tm) Processor 248
//   Intel Dual Core something or other
//
// These values will need to be checked when new CPUs are available or
// when we move to 64 bit executables.

#include <ostream>
#include <string>

namespace art {
  struct MallocOpts {
    using opt_type = int;

    MallocOpts() = default;
    MallocOpts(opt_type max, opt_type trim, opt_type pad, opt_type mmap_thr)
      : mmap_max_(max), trim_thr_(trim), top_pad_(pad), mmap_thr_(mmap_thr)
    {}

    opt_type mmap_max_{};
    opt_type trim_thr_{};
    opt_type top_pad_{};
    opt_type mmap_thr_{};

    bool
    operator==(const MallocOpts& opts) const noexcept
    {
      return mmap_max_ == opts.mmap_max_ && trim_thr_ == opts.trim_thr_ &&
             top_pad_ == opts.top_pad_ && mmap_thr_ == opts.mmap_thr_;
    }
    bool
    operator!=(const MallocOpts& opts) const noexcept
    {
      return !operator==(opts);
    }
  };

  std::ostream& operator<<(std::ostream& ost, const MallocOpts&);

  class MallocOptionSetter {
  public:
    using opt_type = MallocOpts::opt_type;
    MallocOptionSetter();

    bool retrieveFromCpuType();
    bool retrieveFromEnv();
    void adjustMallocParams();
    bool
    hasErrors() const
    {
      return !error_message_.empty();
    }
    std::string
    error_message() const
    {
      return error_message_;
    }

    void
    set_mmap_max(opt_type mmap_max)
    {
      values_.mmap_max_ = mmap_max;
      changed_ = true;
    }
    void
    set_trim_thr(opt_type trim_thr)
    {
      values_.trim_thr_ = trim_thr;
      changed_ = true;
    }
    void
    set_top_pad(opt_type top_pad)
    {
      values_.top_pad_ = top_pad;
      changed_ = true;
    }
    void
    set_mmap_thr(opt_type mmap_thr)
    {
      values_.mmap_thr_ = mmap_thr;
      changed_ = true;
    }

    MallocOpts
    get() const
    {
      return values_;
    }

  private:
    bool changed_;
    MallocOpts values_;

    std::string error_message_;
  };

} // namespace art

#endif /* art_Utilities_MallocOpts_h */

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