cpu_mac.cc revision 4e51691e58d8d32590b03c1951cb13de4d1c4758 
1/*
2 *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
3 *
4 *  Use of this source code is governed by a BSD-style license
5 *  that can be found in the LICENSE file in the root of the source
6 *  tree. An additional intellectual property rights grant can be found
7 *  in the file PATENTS.  All contributing project authors may
8 *  be found in the AUTHORS file in the root of the source tree.
9 */
10
11#include "cpu_mac.h"
12
13#include <iostream>
14#include <mach/mach.h>
15#include <mach/mach_error.h>
16
17#include "tick_util.h"
18
19namespace webrtc {
20CpuWrapperMac::CpuWrapperMac() : _cpuUsage(NULL)
21{
22    natural_t cpuCount;
23    processor_info_array_t infoArray;
24    mach_msg_type_number_t infoCount;
25
26    kern_return_t error = host_processor_info(mach_host_self(),
27                                              PROCESSOR_CPU_LOAD_INFO,
28                                              &cpuCount,
29                                              &infoArray,
30                                              &infoCount);
31    if (error)
32    {
33        return;
34    }
35
36    _cpuUsage = new WebRtc_UWord32[cpuCount];
37    _lastTickCount = new WebRtc_Word64[cpuCount];
38    _lastTime = TickTime::MillisecondTimestamp();
39
40    processor_cpu_load_info_data_t* cpuLoadInfo =
41        (processor_cpu_load_info_data_t*) infoArray;
42    for (unsigned int cpu= 0; cpu < cpuCount; cpu++)
43    {
44        WebRtc_Word64 ticks = 0;
45        for (int state = 0; state < 2; state++)
46        {
47            ticks += cpuLoadInfo[cpu].cpu_ticks[state];
48        }
49        _lastTickCount[cpu] = ticks;
50    }
51    vm_deallocate(mach_task_self(), (vm_address_t)infoArray, infoCount);
52}
53
54CpuWrapperMac::~CpuWrapperMac()
55{
56    delete _cpuUsage;
57    delete _lastTickCount;
58}
59
60WebRtc_Word32 CpuWrapperMac::CpuUsage()
61{
62    WebRtc_UWord32 numCores;
63    WebRtc_UWord32* array = NULL;
64    return CpuUsageMultiCore(numCores, array);
65}
66
67WebRtc_Word32
68CpuWrapperMac::CpuUsageMultiCore(WebRtc_UWord32& numCores,
69                                 WebRtc_UWord32*& array)
70{
71    natural_t cpuCount;
72    processor_info_array_t infoArray;
73    mach_msg_type_number_t infoCount;
74
75    // sanity check
76    if(_cpuUsage == NULL)
77    {
78        return -1;
79    }
80    WebRtc_Word64 now = TickTime::MillisecondTimestamp();
81    WebRtc_Word64 timeDiffMS = now - _lastTime;
82    // TODO(hellner) why block here? Why not just return the old
83    //                          value? Is this behavior consistent across all
84    //                          platforms?
85    // Make sure that at least 500 ms pass between calls.
86    if(timeDiffMS < 500)
87    {
88        usleep((500-timeDiffMS)*1000);
89        return CpuUsageMultiCore(numCores, array);
90    }
91    _lastTime = now;
92
93     kern_return_t error = host_processor_info(mach_host_self(),
94                                              PROCESSOR_CPU_LOAD_INFO,
95                                              &cpuCount,
96                                              &infoArray,
97                                              &infoCount);
98    if (error)
99    {
100        return -1;
101    }
102
103    processor_cpu_load_info_data_t* cpuLoadInfo =
104        (processor_cpu_load_info_data_t*) infoArray;
105
106    WebRtc_Word32 totalCpuUsage = 0;
107    for (unsigned int cpu = 0; cpu < cpuCount; cpu++)
108    {
109        WebRtc_Word64 ticks = 0;
110        for (int state = 0; state < 2; state++)
111        {
112            ticks += cpuLoadInfo[cpu].cpu_ticks[state];
113        }
114        if(timeDiffMS <= 0)
115        {
116            _cpuUsage[cpu] = 0;
117        }else {
118            _cpuUsage[cpu] = (WebRtc_UWord32)((1000 *
119                                              (ticks - _lastTickCount[cpu])) /
120                                              timeDiffMS);
121        }
122        _lastTickCount[cpu] = ticks;
123        totalCpuUsage += _cpuUsage[cpu];
124    }
125
126    vm_deallocate(mach_task_self(), (vm_address_t)infoArray, infoCount);
127
128    numCores = cpuCount;
129    array = _cpuUsage;
130    return totalCpuUsage/cpuCount;
131}
132} // namespace webrtc
133