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(python2.1-lib.info)Resource Usage

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Resource Usage
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These functiona are used to retrieve resource usage information:

`getrusage(who)'
     This function returns a large tuple that describes the resources
     consumed by either the current process or its children, as
     specified by the WHO parameter.  The WHO parameter should be
     specified using one of the `RUSAGE_*' constants described below.

     The elements of the return value each describe how a particular
     system resource has been used, e.g. amount of time spent running
     is user mode or number of times the process was swapped out of
     main memory. Some values are dependent on the clock tick internal,
     e.g. the amount of memory the process is using.

     The first two elements of the return value are floating point
     values representing the amount of time spent executing in user
     mode and the amount of time spent executing in system mode,
     respectively. The remaining values are integers. Consult the
     `getrusage(2)' man page for detailed information about these
     values. A brief summary is presented here:

     Offset                             Resource
     ------                             -----
     0                                  time in user mode (float)
     1                                  time in system mode (float)
     2                                  maximum resident set size
     3                                  shared memory size
     4                                  unshared memory size
     5                                  unshared stack size
     6                                  page faults not requiring I/O
     7                                  page faults requiring I/O
     8                                  number of swap outs
     9                                  block input operations
     10                                 block output operations
     11                                 messages sent
     12                                 messages received
     13                                 signals received
     14                                 voluntary context switches
     15                                 involuntary context switches

     This function will raise a `ValueError' if an invalid WHO
     parameter is specified. It may also raise `error' exception in
     unusual circumstances.

`getpagesize()'
     Returns the number of bytes in a system page. (This need not be the
     same as the hardware page size.) This function is useful for
     determining the number of bytes of memory a process is using. The
     third element of the tuple returned by `getrusage()' describes
     memory usage in pages; multiplying by page size produces number of
     bytes.

The following `RUSAGE_*' symbols are passed to the `getrusage()'
function to specify which processes information should be provided for.

`RUSAGE_SELF'
     `RUSAGE_SELF' should be used to request information pertaining
     only to the process itself.

`RUSAGE_CHILDREN'
     Pass to `getrusage()' to request resource information for child
     processes of the calling process.

`RUSAGE_BOTH'
     Pass to `getrusage()' to request resources consumed by both the
     current process and child processes.  May not be available on all
     systems.