09-21-2001
If you and I are on the system and we both run vi to edit different files, no modern kernel will give us two complete seperate copies of vi. The program's memory will be broken into segments. The text segment contains (roughly) the code and the unchanging constants. We will share one text segment bewteen us. We each get a data segment and we each get a stack. top will report the total of all the segments for each process, but you can't add them up and expect that system needs to use that much physical memory. With shared libraries, it get a bit more confused. If you use emacs and I use vi, will we have different text segments, but we both might be using the same copy of printf and other library functions. Oracle is probably using shared memory which further complicates things. Shared memory is another memory segment, and again many processes can map that seqment into their memory space. So 100 copies of a 700 MB program might easily fit in a couple of GB of memory.
In view of all this, it really isn't possible anymore to truly say how much memory a single process is using in the sense that you want. Each process really is using 700MB, but they are sharing very large chucks of this with other processes.
Most versions of top have a line that shows system-wide memory usage.
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LEARN ABOUT HPUX
serialize
serialize(1) General Commands Manual serialize(1)
NAME
serialize - force target process to run serially with other processes
SYNOPSIS
command [command_args]
pid]
DESCRIPTION
The command is used to force the target process to run serially with other processes also marked by this command. The target process can
be referred to by pid value, or it can be invoked directly on the command. Once a process has been marked by the process stays marked
until process completion unless is reissued on the serialized process with the option. The option causes the pid specified with the option
to return to normal timeshare scheduling algorithms.
This call is used to improve process throughput, since process throughput usually increases for large processes when they are executed
serially instead of allowing each program to run for only a short period of time. By running large processes one at a time, the system
makes more efficient use of the CPU as well as system memory, since each process does not end up constantly faulting in its working set, to
only have the pages stolen when another process starts running. As long as there is enough memory in the system, processes marked by
behave no differently from other processes in the system. However, once memory becomes tight, processes marked by are run one at a time
with the highest priority processes being run first. Each process will run for a finite interval of time before another serialized process
is allowed to run.
Options
supports the following options:
Indicates the process specified by
pid should be returned to timeshare scheduling.
Indicates the
pid of the target process.
If neither option is specified, is invoked on the command line passed in.
RETURN VALUE
returns the following value:
Successful completion.
Invalid
pid specification, nonnumeric entry, or pid specification is that of a special system process.
Could not execute the specified command.
No such process.
Must be root or a member of a group having the
privilege to execute
ERRORS
fails under the following condition and sets (see errno(2)) to the following value:
The pid passed in does not exist.
EXAMPLES
Use to force a database application to run serially with other processes marked for serialization:
Force a currently running process with a pid value of 215 to run serially with other processes marked for serialization:
Return a process previously marked for serialization to normal timeshare scheduling. The pid of the target process for this example is
WARNINGS
The user has no way of forcing an execution order on serialized processes.
AUTHOR
was developed by HP.
SEE ALSO
setprivgrp(1M), getprivgrp(2), serialize(2).
serialize(1)