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PIDSTAT(1)                    Linux User's Manual                   PIDSTAT(1)



NAME
       pidstat - Report statistics for Linux tasks.

SYNOPSIS
       pidstat  [ -C comm ] [ -d ] [ -h ] [ -I ] [ -l ] [ -p { pid [,...] | SELF | ALL } ] [ -r ] [ -t ] [ -T { TASK |
       CHILD | ALL } ] [ -u ] [ -V ] [ -w ] [ interval [ count ] ]

DESCRIPTION
       The pidstat command is used for monitoring individual tasks currently being managed by the  Linux  kernel.   It
       writes  to  standard  output activities for every task selected with option -p or for every task managed by the
       Linux kernel if option -p ALL has been used. Not selecting any tasks is equivalent to  specifying  -p  ALL  but
       only active tasks (tasks with non-zero statistics values) will appear in the report.

       The  pidstat  command can also be used for monitoring the child processes of selected tasks.  Read about option
       -T below.

       The interval parameter specifies the amount of time in seconds between each report.  A value of 0 (or no param-
       eters at all) indicates that tasks statistics are to be reported for the time since system startup (boot).  The
       count parameter can be specified in conjunction with the interval parameter if this one is not set to zero. The
       value  of count determines the number of reports generated at interval seconds apart. If the interval parameter
       is specified without the count parameter, the pidstat command generates reports continuously.

       You can select information about specific task activities using flags.  Not specifying any flags  selects  only
       CPU activity.


OPTIONS
       -C comm
              Display only tasks whose command name includes the string comm.

       -d     Report I/O statistics (kernels 2.6.20 and later only).  The following values are displayed:

              PID
                     The identification number of the task being monitored.

              kB_rd/s
                     Number of kilobytes the task has caused to be read from disk per second.

              kB_wr/s
                     Number of kilobytes the task has caused, or shall cause to be written to disk per second.

              kB_ccwr/s
                     Number of kilobytes whose writing to disk has been cancelled by the task. This may occur when the
                     task truncates some dirty pagecache. In this case, some IO which another task has been  accounted
                     for will not be happening.

              Command
                     The command name of the task.

       -h     Display all activities horizontally on a single line. This is intended to make it easier to be parsed by
              other programs.

       -I     In an SMP environment, indicate that tasks CPU usage (as displayed by option -u ) should be  divided  by
              the total number of processors.

       -l     Display the process command name and all its arguments.

       -p { pid [,...] | SELF | ALL }
              Select  tasks  (processes)  for  which statistics are to be reported.  pid is the process identification
              number. The SELF keyword indicates that statistics are to be reported for the  pidstat  process  itself,
              whereas  the  ALL  keyword indicates that statistics are to be reported for all the tasks managed by the
              system.

       -r     Report page faults and memory utilization.

              When reporting statistics for individual tasks, the following values are displayed:

              PID
                     The identification number of the task being monitored.

              minflt/s
                     Total number of minor faults the task has made per second, those which have not required  loading
                     a memory page from disk.

              majflt/s
                     Total  number  of  major faults the task has made per second, those which have required loading a
                     memory page from disk.

              VSZ
                     Virtual Size: The virtual memory usage of entire task in kilobytes.

              RSS
                     Resident Set Size: The non-swapped physical memory used by the task in kilobytes.

              Command
                     The command name of the task.

              When reporting global statistics for tasks and all their children, the following values are displayed:

              PID
                     The identification number of the task which is being monitored together with its children.

              minflt-nr
                     Total number of minor faults made by the task and all its  children,  and  collected  during  the
                     interval of time.

              majflt-nr
                     Total  number  of  major  faults  made by the task and all its children, and collected during the
                     interval of time.

              Command
                     The command name of the task which is being monitored together with its children.

       -t     Also display statistics for threads associated with selected tasks.

              This option adds the following values to the reports:

              TGID
                     The identification number of the thread group leader.

              TID
                     The identification number of the thread being monitored.

       -T { TASK | CHILD | ALL }
              This option specifies what has to be monitored by the pidstat command. The TASK keyword  indicates  that
              statistics  are  to be reported for individual tasks (this is the default option) whereas the CHILD key-
              word indicates that statistics are to be globally reported for the selected tasks and  all  their  chil-
              dren. The ALL keyword indicates that statistics are to be reported for individual tasks and globally for
              the selected tasks and their children.

              Note: Global statistics for tasks and all their children are not available for all options  of  pidstat.
              Also  these  statistics are not necessarily relevant to current time interval: The statistics of a child
              process are collected only when it finishes or it is killed.

       -u     Report CPU utilization.

              When reporting statistics for individual tasks, the following values are displayed:

              PID
                     The identification number of the task being monitored.

              %usr
                     Percentage of CPU used by the task while executing at the user level (application), with or with-
                     out  nice priority. Note that this field does NOT include time spent running a virtual processor.

              %system
                     Percentage of CPU used by the task while executing at the system level (kernel).

              %guest
                     Percentage of CPU spent by the task in virtual machine (running a virtual processor).

              %CPU
                     Total percentage of CPU time used by the task. In an SMP environment, the task's CPU  usage  will
                     be divided by the total number of CPU's if option -I has been entered on the command line.

              CPU
                     Processor number to which the task is attached.

              Command
                     The command name of the task.

              When reporting global statistics for tasks and all their children, the following values are displayed:

              PID
                     The identification number of the task which is being monitored together with its children.

              usr-ms
                     Total  number  of milliseconds spent by the task and all its children while executing at the user
                     level (application), with or without nice priority, and collected during the  interval  of  time.
                     Note that this field does NOT include time spent running a virtual processor.

              system-ms
                     Total number of milliseconds spent by the task and all its children while executing at the system
                     level (kernel), and collected during the interval of time.

              guest-ms
                     Total number of milliseconds spent by the task and all its children in virtual machine (running a
                     virtual processor).

              Command
                     The command name of the task which is being monitored together with its children.

       -V     Print version number then exit.

       -w     Report task switching activity (kernels 2.6.23 and later only).  The following values are displayed:

              PID
                     The identification number of the task being monitored.

              cswch/s
                     Total  number of voluntary context switches the task made per second.  A voluntary context switch
                     occurs when a task blocks because it requires a resource that is unavailable.

              nvcswch/s
                     Total number of non voluntary context switches the task made per second.  A  involuntary  context
                     switch  takes place when a task executes for the duration of its time slice and then is forced to
                     relinquish the processor.

              Command
                     The command name of the task.

ENVIRONMENT
       The pidstat command takes into account the following environment variable:


       S_TIME_FORMAT
              If this variable exists and its value is ISO then the current locale will be ignored when  printing  the
              date in the report header.  The pidstat command will use the ISO 8601 format (YYYY-MM-DD) instead.


EXAMPLES
       pidstat 2 5
              Display five reports of CPU statistics for every active task in the system at two second intervals.

       pidstat -r -p 1643 2 5
              Display five reports of page faults and memory statistics for PID 1643 at two second intervals.

       pidstat -T CHILD -r 2 5
              Display  five  reports  of page faults statistics at two second intervals for the child processes of all
              tasks in the system. Only child processes with non-zero statistics values are displayed.

BUGS
       /proc filesystem must be mounted for the pidstat command to work.


FILES
       /proc contains various files with system statistics.


AUTHOR
       Sebastien Godard (sysstat <at> orange.fr)

SEE ALSO
       sar(1), top(1), ps(1), mpstat(1), iostat(1), vmstat(8)

       http://pagesperso-orange.fr/sebastien.godard/



Linux                            DECEMBER 2008                      PIDSTAT(1)