stack_dist.cc revision 11430:bd1c6789c33f 
1/*
2 * Copyright (c) 2015 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 hereunder.  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: Andreas Sandberg
38 */
39
40#include "mem/probes/stack_dist.hh"
41
42#include "params/StackDistProbe.hh"
43#include "sim/system.hh"
44
45StackDistProbe::StackDistProbe(StackDistProbeParams *p)
46    : BaseMemProbe(p),
47      lineSize(p->line_size),
48      disableLinearHists(p->disable_linear_hists),
49      disableLogHists(p->disable_log_hists),
50      calc(p->verify)
51{
52    fatal_if(p->system->cacheLineSize() > p->line_size,
53             "The stack distance probe must use a cache line size that is "
54             "larger or equal to the system's cahce line size.");
55}
56
57void
58StackDistProbe::regStats()
59{
60    const StackDistProbeParams *p(
61        dynamic_cast<const StackDistProbeParams *>(params()));
62    assert(p);
63
64    using namespace Stats;
65
66    readLinearHist
67        .init(p->linear_hist_bins)
68        .name(name() + ".readLinearHist")
69        .desc("Reads linear distribution")
70        .flags(disableLinearHists ? nozero : pdf);
71
72    readLogHist
73        .init(p->log_hist_bins)
74        .name(name() + ".readLogHist")
75        .desc("Reads logarithmic distribution")
76        .flags(disableLogHists ? nozero : pdf);
77
78    writeLinearHist
79        .init(p->linear_hist_bins)
80        .name(name() + ".writeLinearHist")
81        .desc("Writes linear distribution")
82        .flags(disableLinearHists ? nozero : pdf);
83
84    writeLogHist
85        .init(p->log_hist_bins)
86        .name(name() + ".writeLogHist")
87        .desc("Writes logarithmic distribution")
88        .flags(disableLogHists ? nozero : pdf);
89
90    infiniteSD
91        .name(name() + ".infinity")
92        .desc("Number of requests with infinite stack distance")
93        .flags(nozero);
94}
95
96void
97StackDistProbe::handleRequest(const ProbePoints::PacketInfo &pkt_info)
98{
99    // only capturing read and write requests (which allocate in the
100    // cache)
101    if (!pkt_info.cmd.isRead() && !pkt_info.cmd.isWrite())
102        return;
103
104    // Align the address to a cache line size
105    const Addr aligned_addr(roundDown(pkt_info.addr, lineSize));
106
107    // Calculate the stack distance
108    const uint64_t sd(calc.calcStackDistAndUpdate(aligned_addr).first);
109    if (sd == StackDistCalc::Infinity) {
110        infiniteSD++;
111        return;
112    }
113
114    // Sample the stack distance of the address in linear bins
115    if (!disableLinearHists) {
116        if (pkt_info.cmd.isRead())
117            readLinearHist.sample(sd);
118        else
119            writeLinearHist.sample(sd);
120    }
121
122    if (!disableLogHists) {
123        int sd_lg2 = sd == 0 ? 1 : floorLog2(sd);
124
125        // Sample the stack distance of the address in log bins
126        if (pkt_info.cmd.isRead())
127            readLogHist.sample(sd_lg2);
128        else
129            writeLogHist.sample(sd_lg2);
130    }
131}
132
133
134StackDistProbe *
135StackDistProbeParams::create()
136{
137    return new StackDistProbe(this);
138}
139