random_gen.cc revision 12396 
1/*
2 * Copyright (c) 2012-2013, 2016-2017 ARM Limited
3 * All rights reserved
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed here under.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Redistribution and use in source and binary forms, with or without
15 * modification, are permitted provided that the following conditions are
16 * met: redistributions of source code must retain the above copyright
17 * notice, this list of conditions and the following disclaimer;
18 * redistributions in binary form must reproduce the above copyright
19 * notice, this list of conditions and the following disclaimer in the
20 * documentation and/or other materials provided with the distribution;
21 * neither the name of the copyright holders nor the names of its
22 * contributors may be used to endorse or promote products derived from
23 * this software without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
26 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
27 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
28 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
36 *
37 * Authors: Thomas Grass
38 *          Andreas Hansson
39 *          Sascha Bischoff
40 *          Neha Agarwal
41 */
42
43#include "cpu/testers/traffic_gen/random_gen.hh"
44
45#include <algorithm>
46
47#include "base/random.hh"
48#include "base/trace.hh"
49#include "debug/TrafficGen.hh"
50#include "proto/packet.pb.h"
51
52void
53RandomGen::enter()
54{
55    // reset the counter to zero
56    dataManipulated = 0;
57}
58
59PacketPtr
60RandomGen::getNextPacket()
61{
62    // choose if we generate a read or a write here
63    bool isRead = readPercent != 0 &&
64        (readPercent == 100 || random_mt.random(0, 100) < readPercent);
65
66    assert((readPercent == 0 && !isRead) || (readPercent == 100 && isRead) ||
67           readPercent != 100);
68
69    // address of the request
70    Addr addr = random_mt.random(startAddr, endAddr - 1);
71
72    // round down to start address of block
73    addr -= addr % blocksize;
74
75    DPRINTF(TrafficGen, "RandomGen::getNextPacket: %c to addr %x, size %d\n",
76            isRead ? 'r' : 'w', addr, blocksize);
77
78    // add the amount of data manipulated to the total
79    dataManipulated += blocksize;
80
81    // create a new request packet
82    return getPacket(addr, blocksize,
83                     isRead ? MemCmd::ReadReq : MemCmd::WriteReq);
84}
85
86Tick
87RandomGen::nextPacketTick(bool elastic, Tick delay) const
88{
89    // Check to see if we have reached the data limit. If dataLimit is
90    // zero we do not have a data limit and therefore we will keep
91    // generating requests for the entire residency in this state.
92    if (dataLimit && dataManipulated >= dataLimit)
93    {
94        DPRINTF(TrafficGen, "Data limit for RandomGen reached.\n");
95        // No more requests. Return MaxTick.
96        return MaxTick;
97    } else {
98        // return the time when the next request should take place
99        Tick wait = random_mt.random(minPeriod, maxPeriod);
100
101        // compensate for the delay experienced to not be elastic, by
102        // default the value we generate is from the time we are
103        // asked, so the elasticity happens automatically
104        if (!elastic) {
105            if (wait < delay)
106                wait = 0;
107            else
108                wait -= delay;
109        }
110
111        return curTick() + wait;
112    }
113}
114