Which of the following commands will only provide a snapshot of average memory usage for a process？（）

单项选择题Whichofthefollowingcommandsshouldbeusedtomonitorthenumberofthreadsonthescheduler’srunqueueforanygiveninterval？（）

A. sar
B. pstat
C. iostat
D. filemon

单项选择题Whenmonitoringasystemusingvmstatwithaninterval，whichofthefollowingconclusionsshouldbedrawnaboutthemetricsunderpagepiandpagepo？（）

A. The values do not include working storage.
B. The values do not include persistent storage.
C. The values include both persistent and working storage.
D. The values are not working or persistent storage.

单项选择题To examine the Exhibit， press the Exhibit button. While a user is compiling a C program，  vmstat 120 10  is run to determine the cause of a performance problem.  Given the vmstat output as shown in the exhibit， which of the following conclusions is most appropriate to draw about the machine？（）

A. The machine has too many users.
B. The machine has an I/O bottleneck.
C. The machine has a CPU bottleneck.
D. The machine has a memory bottleneck.

单项选择题Inaniostatreport，whichofthefollowingoptionsbestdescribesthevalueof%tm_act？（）

A. The total CPU usage for this drive
B. The bandwidth utilization of the indicated drive
C. It can best be represented by the equation （%iowait - %ioidle）
D. It can best be represented by the equation （kilobytes read/kilobytes written） *100

单项选择题Whichofthefollowingcommandsshouldbeusedtomonitortheaveragenumberofthreadsinthescheduler’srunqueueforanygiveninterval？（）

A. tprof
B. iostat
C. vmstat
D. filemon