android cpu 利用率

proc/$PID/stat文件中的值  

其內容14~17 列  ：

       seq_put_decimal_ull(m, ' ', cputime_to_clock_t(utime));

        seq_put_decimal_ull(m, ' ', cputime_to_clock_t(stime));

        seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cutime));

        seq_put_decimal_ll(m, ' ', cputime_to_clock_t(cstime));

的四位數字分別是:

utime該任務在用戶運行狀態的時間

stime該任務在覈心運行的時間

cutime全部已死線程在用戶狀態運行狀態的時間

cstime全部已死線程在覈心的運行時間

因此processCpuTime爲這個四個屬性的和.

當前進行所佔CPU的算法是:

100*(processCpuTimeS-processCpuTimeF)/(totalCpuTimeS-totalCpuTimeF)

 

 

內存：

http://blog.csdn.net/jackjones_008/article/details/41944973

http://www.cnblogs.com/adv-qbj/p/4719787.html

http://gityuan.com/2016/01/02/memory-analysis-command/

1. Active = Active(anon) + Active(file) Inactive = Inactive(anon) + Inactive(file)
2. Active(file), Inactive(file) has file back-end which means its original file is in disk but to use it faster it was loaded on RAM.
3. Active(file) + Inactive(file) + Shmem = Cached + Buffer + SwapCached