stats.h

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// stats.h 
//      Data structures for gathering statistics about Nachos performance.
//
// DO NOT CHANGE -- these stats are maintained by the machine emulation
//
//
// Copyright (c) 1992-1993 The Regents of the University of California.
// All rights reserved.  See copyright.h for copyright notice and limitation 
// of liability and disclaimer of warranty provisions.

#ifndef STATS_H
#define STATS_H

#include "copyright.h"

// The following class defines the statistics that are to be kept
// about Nachos behavior -- how much time (ticks) elapsed, how
// many user instructions executed, etc.
//
// The fields in this class are public to make it easier to update.

class Statistics {
  public:
    int totalTicks;             // Total time running Nachos
    int idleTicks;              // Time spent idle (no threads to run)
    int systemTicks;            // Time spent executing system code
    int userTicks;              // Time spent executing user code
                                // (this is also equal to # of
                                // user instructions executed)

    int numDiskReads;           // number of disk read requests
    int numDiskWrites;          // number of disk write requests
    int numConsoleCharsRead;    // number of characters read from the keyboard
    int numConsoleCharsWritten; // number of characters written to the display
    int numPageFaults;          // number of virtual memory page faults
    int numPacketsSent;         // number of packets sent over the network
    int numPacketsRecvd;        // number of packets received over the network

    Statistics();               // initialize everything to zero

    void Print();               // print collected statistics
};

// Constants used to reflect the relative time an operation would
// take in a real system.  A "tick" is a just a unit of time -- if you 
// like, a microsecond.
//
// Since Nachos kernel code is directly executed, and the time spent
// in the kernel measured by the number of calls to enable interrupts,
// these time constants are none too exact.

const int UserTick =       1;   // advance for each user-level instruction 
const int SystemTick =    10;   // advance each time interrupts are enabled
const int RotationTime = 500;   // time disk takes to rotate one sector
const int SeekTime =     500;   // time disk takes to seek past one track
const int ConsoleTime =  100;   // time to read or write one character
const int NetworkTime =  100;   // time to send or receive one packet
const int TimerTicks =   100;   // (average) time between timer interrupts

#endif // STATS_H

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