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PIDSTAT(1) Linux User's Manual PIDSTAT(1)
NAME
pidstat - Report statistics for Linux tasks.
SYNOPSIS
pidstat [ -C comm ] [ -d ] [ -I ] [ -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 parameters at all) indicates that tasks statistics are to be reported
for the time since system startup (boot). The count parameter can be specified in con-
junction 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.
-I In an SMP environment, indicate that tasks CPU usage (as displayed by option -u )
should be divided by the total number of processors.
-p { pid | SELF | ALL }
Select tasks (processes) for which statistics are to be reported. pid is the pro-
cess 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 kilo-
bytes.
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 col-
lected during the interval of time.
majflt-nr
Total number of major faults made by the task and all its children, and col-
lected 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 value to the reports:
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 keyword indicates that statistics are to be
globally reported for the selected tasks and all their children. 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 fin-
ishes 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.
%user
Percentage of CPU used by the task while executing at the user level (appli-
cation), with or without nice priority.
%system
Percentage of CPU used by the task while executing at the system level (ker-
nel).
%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.
user-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.
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.
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 val-
ues 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 vol-
untary 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 sec-
ond 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 OCTOBER 2007 PIDSTAT(1)
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