src/cpu/kvm/perfevent.cc

   1 /*
   2  * Copyright (c) 2012 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 <fcntl.h>
  41 #include <sys/ioctl.h>
  42 #include <sys/mman.h>
  43 #include <sys/syscall.h>
  44 #include <sys/types.h>
  45 #include <syscall.h>
  46 #include <unistd.h>
  47
  48 #include <cassert>
  49 #include <cerrno>
  50 #include <csignal>
  51 #include <cstring>
  52
  53 #include "base/logging.hh"
  54 #include "perfevent.hh"
  55
  56 PerfKvmCounterConfig::PerfKvmCounterConfig(uint32_t type, uint64_t config)
  57 {
  58     memset(&attr, 0, sizeof(attr));
  59
  60     attr.size = PERF_ATTR_SIZE_VER0;
  61     attr.type = type;
  62     attr.config = config;
  63 }
  64
  65 PerfKvmCounterConfig::~PerfKvmCounterConfig()
  66 {
  67 }
  68
  69
  70 PerfKvmCounter::PerfKvmCounter(PerfKvmCounterConfig &config, pid_t tid)
  71     : fd(-1), ringBuffer(NULL), pageSize(-1)
  72 {
  73     attach(config, tid, -1);
  74 }
  75
  76 PerfKvmCounter::PerfKvmCounter(PerfKvmCounterConfig &config,
  77                          pid_t tid, const PerfKvmCounter &parent)
  78     : fd(-1), ringBuffer(NULL), pageSize(-1)
  79 {
  80     attach(config, tid, parent);
  81 }
  82
  83 PerfKvmCounter::PerfKvmCounter()
  84     : fd(-1), ringBuffer(NULL), pageSize(-1)
  85 {
  86 }
  87
  88 PerfKvmCounter::~PerfKvmCounter()
  89 {
  90     if (attached())
  91         detach();
  92 }
  93
  94 void
  95 PerfKvmCounter::detach()
  96 {
  97     assert(attached());
  98
  99     if (munmap(ringBuffer, ringNumPages * pageSize) == -1)
 100         warn("PerfKvmCounter: Failed to unmap ring buffer (%i)\n",
 101              errno);
 102     close(fd);
 103
 104     fd = -1;
 105     ringBuffer = NULL;
 106 }
 107
 108 void
 109 PerfKvmCounter::start()
 110 {
 111     if (ioctl(PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1)
 112         panic("KVM: Failed to enable performance counters (%i)\n", errno);
 113 }
 114
 115 void
 116 PerfKvmCounter::stop()
 117 {
 118     if (ioctl(PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1)
 119         panic("KVM: Failed to disable performance counters (%i)\n", errno);
 120 }
 121
 122 void
 123 PerfKvmCounter::period(uint64_t period)
 124 {
 125     if (ioctl(PERF_EVENT_IOC_PERIOD, &period) == -1)
 126         panic("KVM: Failed to set period of performance counter (%i)\n", errno);
 127 }
 128
 129 void
 130 PerfKvmCounter::refresh(int refresh)
 131 {
 132     if (ioctl(PERF_EVENT_IOC_REFRESH, refresh) == -1)
 133         panic("KVM: Failed to refresh performance counter (%i)\n", errno);
 134 }
 135
 136 uint64_t
 137 PerfKvmCounter::read() const
 138 {
 139     uint64_t value;
 140
 141     read(&value, sizeof(uint64_t));
 142     return value;
 143 }
 144
 145 void
 146 PerfKvmCounter::enableSignals(pid_t tid, int signal)
 147 {
 148     struct f_owner_ex sigowner;
 149
 150     sigowner.type = F_OWNER_TID;
 151     sigowner.pid = tid;
 152
 153     if (fcntl(F_SETOWN_EX, &sigowner) == -1 ||
 154         fcntl(F_SETSIG, signal) == -1 ||
 155         fcntl(F_SETFL, O_ASYNC) == -1)
 156         panic("PerfKvmCounter: Failed to enable signals for counter (%i)\n",
 157               errno);
 158 }
 159
 160 void
 161 PerfKvmCounter::attach(PerfKvmCounterConfig &config,
 162                     pid_t tid, int group_fd)
 163 {
 164     assert(!attached());
 165
 166     fd = syscall(__NR_perf_event_open,
 167                  &config.attr, tid,
 168                  -1, // CPU (-1 => Any CPU that the task happens to run on)
 169                  group_fd,
 170                  0); // Flags
 171     if (fd == -1)
 172     {
 173         if (errno == EACCES)
 174         {
 175             panic("PerfKvmCounter::attach recieved error EACCESS\n"
 176             "  This error may be caused by a too restrictive setting\n"
 177             "  in the file '/proc/sys/kernel/perf_event_paranoid'\n"
 178             "  The default value was changed to 2 in kernel 4.6\n"
 179             "  A value greater than 1 prevents gem5 from making\n"
 180             "  the syscall to perf_event_open");
 181         }
 182         panic("PerfKvmCounter::attach failed (%i)\n", errno);
 183     }
 184
 185     mmapPerf(1);
 186 }
 187
 188 pid_t
 189 PerfKvmCounter::sysGettid()
 190 {
 191     return syscall(__NR_gettid);
 192 }
 193
 194 void
 195 PerfKvmCounter::mmapPerf(int pages)
 196 {
 197     assert(attached());
 198     assert(ringBuffer == NULL);
 199
 200     if (pageSize == -1) {
 201         pageSize = sysconf(_SC_PAGE_SIZE);
 202         if (pageSize == -1)
 203             panic("PerfKvmCounter: Failed to determine page size (%i)\n",
 204                   errno);
 205     }
 206
 207     ringNumPages = pages + 1;
 208     ringBuffer = (struct perf_event_mmap_page *)mmap(
 209         NULL, ringNumPages * 4096,
 210         PROT_READ | PROT_WRITE, MAP_SHARED,
 211         fd, 0);
 212     if (ringBuffer == MAP_FAILED)
 213         panic("PerfKvmCounter: MMAP failed (%i)\n",
 214               errno);
 215 }
 216
 217 int
 218 PerfKvmCounter::fcntl(int cmd, long p1)
 219 {
 220     assert(attached());
 221     return ::fcntl(fd, cmd, p1);
 222 }
 223
 224 int
 225 PerfKvmCounter::ioctl(int request, long p1)
 226 {
 227     assert(attached());
 228     return ::ioctl(fd, request, p1);
 229 }
 230
 231 void
 232 PerfKvmCounter::read(void *buf, size_t size) const
 233 {
 234     char *_buf = (char *)buf;
 235     size_t _size = size;
 236
 237     assert(attached());
 238
 239     do {
 240         ssize_t ret;
 241         ret = ::read(fd, _buf, _size);
 242         switch (ret) {
 243           case -1:
 244             if (errno != EAGAIN)
 245                 panic("PerfKvmCounter::read failed (%i)\n", errno);
 246             break;
 247
 248           case 0:
 249             panic("PerfKvmCounter::read unexpected EOF.\n");
 250
 251           default:
 252             _size -= ret;
 253             _buf += ret;
 254             break;
 255         }
 256     } while (_size);
 257 }