[Rk_2014_0918]linux, test the effect of usleep function on CPU utilization

First, the native environment

CPU Information Intel (R) Core (TM) i3 CPU    -  2 . 27GHz

Intel (R) Core (TM) i3 CPU  M  @ 2.27GHz

Intel (R) Core (TM) i3 CPU  M  @ 2. 27GHz

Intel (R) Core (TM) i3 CPU  M  @ 2. 27GHz

Memory information
1990228 KB

Second, build the test code

1. Test code

#include <iostream>#include<unistd.h>using namespacestd;#defineElapsedTime 1intMain (void) {cout<<"Current pid:"<< getpid () <<Endl;
     while(1)    {        //Usleep (elapsedtime);    }    return 0;}

2. Compiling

# g++-O test_usleep.o test_usleep.cpp

3. Running

#./TEST_USLEEP.O

Third, CPU occupancy rate

Note: When testing TEST_USLEEP.O, do not run other programs.

1. No "usleep (elapsedtime);" This line of code

CPU usage:99.9%%cpu%MEM time+954003368893  76099.90.00:07.52

2. #define ELAPSEDTIME 1//1 μs

CPU usage:99.9%%cpu%MEM time+955603368872  76099.90.00:05.10

3. #define ELAPSEDTIME 10//10 μs

CPU usage:14.0%%cpu%MEM time+959603368868  76014.00.00:09.99 TEST_USLEEP.O

4. #define ELAPSEDTIME 100//100 μs

CPU usage:11.7%%cpu%MEM time+961003368868  76011.70.00:05.16

5. #define ELAPSEDTIME 1000//1000 μs =1 ms

CPU usage:1.7%%cpu%MEM time+962403368868 760 1.7 0.0 0:00.79 TEST_USLEEP.O

6. #define ELAPSEDTIME 10000//10000 μs =10 ms

CPU usage:0.3%%cpu%MEM time+963403368868 760 0.3 0.0 0:00.04

7. #define ELAPSEDTIME 100000//100000 μs =100 ms

CPU usage:0.0%%cpu%MEM time+964403368872 760 0.0 0.0 0:00.00 TEST_USLEEP.O

Iv. Reference Information

1.linux, get CPU information

Cat/proc/cpuinfo

2.linux, get memory information

Cat/proc/meminfo

3.linux, use top to view status information for a single process

Top-p PID

V. Web site

Http://www.cnblogs.com/tom-and-jerry/p/3978797.html

End

[Rk_2014_0918]linux, test the effect of usleep function on CPU utilization