1.3 cat /proc/stat
第一行数据表示cpu的总得使用情况
接着cpu0、cpu1、cpu2、cpu3 表示cpu为四核
第一行的数值表示的是CPU总的使用情况，所以我们只要用第一行的数字计算就可以了。下表解析第一行各数值的含义：
参数 解析（单位：jiffies）
(jiffies是内核中的一个全局变量，用来记录自系统启动一来产生的节拍数，在linux中，一个节拍大致可理解为操作系统进程调度的最小时间片，不同linux内核可能值有不同，通常在1ms到10ms之间)
user ( 15579 ) 从系统启动开始累计到当前时刻，处于用户态的运行时间，不包含 nice值为负进程。
nice (99) 从系统启动开始累计到当前时刻，nice值为负的进程所占用的CPU时间
system (13680) 从系统启动开始累计到当前时刻，处于核心态的运行时间
idle (698457) 从系统启动开始累计到当前时刻，除IO等待时间以外的其它等待时间
iowait (10939) 从系统启动开始累计到当前时刻，IO等待时间(since 2.5.41)
irq (40) 从系统启动开始累计到当前时刻，硬中断时间(since 2.6.0-test4)
softirq (651) 从系统启动开始累计到当前时刻，软中断时间(since 2.6.0-test4)
stealstolen(0) which is the time spent in other operating systems when running in a virtualized environment(since 2.6.11)
guest(0) which is the time spent running a virtual CPU for guest operating systems under the control of the Linux kernel(since 2.6.24)
结论：总的cpu时间totalCpuTime = user + nice + system + idle + iowait + irq + softirq + stealstolen +guest
通过 idle 是cpu空闲时间可以计算出整个cpu的使用率。
1.4 cat /proc/cpuinfo
shell@a3ltechn:/proc $ cat cpuinfo
processor : 0
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 38.40
Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 0
processor : 1
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 38.40
Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 0
processor : 2
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 38.40
Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 0
processor : 3
model name : ARMv7 Processor rev 0 (v7l)
BogoMIPS : 38.40
Features : swp half thumb fastmult vfp edsp neon vfpv3 tls vfpv4 idiva idivt
CPU implementer : 0x41
CPU architecture: 7
CPU variant : 0x0
CPU part : 0xd03
CPU revision : 0
1.7 获取cpu核数 https://github.com/facebook/devi ... ass/DeviceInfo.java
/**
* Reads the number of CPU cores from {@code /sys/devices/system/cpu/}.
*
* @return Number of CPU cores in the phone, or DEVICEINFO_UKNOWN = -1 in the event of an error.
*/
public static int getNumberOfCPUCores() {
if (Build.VERSION.SDK_INT <= Build.VERSION_CODES.GINGERBREAD_MR1) {
// Gingerbread doesn't support giving a single application access to both cores, but a
// handful of devices (Atrix 4G and Droid X2 for example) were released with a dual-core
// chipset and Gingerbread; that can let an app in the background run without impacting
// the foreground application. But for our purposes, it makes them single core.
return 1;
}
int cores;
try {
cores = new File("/sys/devices/system/cpu/").listFiles(CPU_FILTER).length;
} catch (SecurityException e) {
cores = DEVICEINFO_UNKNOWN;
} catch (NullPointerException e) {
cores = DEVICEINFO_UNKNOWN;
}
return cores;
}
private static final FileFilter CPU_FILTER = new FileFilter() {
@Override
public boolean accept(File pathname) {
String path = pathname.getName();
//regex is slow, so checking char by char.
if (path.startsWith("cpu")) {
for (int i = 3; i < path.length(); i++) {
if (!Character.isDigit(path.charAt(i))) {
return false;
}
}
return true;
}
return false;
}
};
QPlayerService: 0.1% user + 0.1% kernel / faults: 2 minor