The KLONDIKE Tool
The KLONDIKE tool is used to load (i.e., fetch) data files into memory. Once loaded in memory,
KLONDIKE can "freeze" that file into memory so that it is immediately accessible to the programs
that require that information. Later, KLONDIKE’s "thaw" command can be used to unload the file
from memory. Freezing commonly used files can have a large impact on performance.
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NOTE In the text of the documentation for KLONDIKE, references made to "page" refer to a logical page of 4,096 bytes.
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Operation
KLONDIKE is a tool that can be used to improve access time to objects that are loaded into
memory. It does this in several ways.
You can use KLONDIKE to fetch a file into memory. What this is really doing is "pre-fetching" a file
into memory. The reason for doing this is that if you know that a given operation would benefit
from having its data in memory, the you can achieve performance gains by prefetching it with
KLONDIKE. For example, when you compile a program, if you fetch the source into memory, then
it will save the operating system the task of checking and possibly loading the source into
memory.
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NOTE Fetching a file into memory does not guarantee that it will stay
there. On a busy system or a system without much "user memory"
(see "The PAGES Tool" on page 143 for a description of user
memory) the likelihood is high that your data will at least be
partially swapped out before you access it. Also, on systems with
low amounts of memory, it may not be possible to fetch an entire
file into memory.
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You can use KLONDIKE to freeze a file into memory. This is similar to fetching except a frozen file
will not be swapped out like a fetched file would. KLONDIKE’s "unfreeze" or "thaw" commands will
free up that frozen file. Freezing a file into memory guarantees better access to the file. Keep in
mind though that you could actually reduce system performance, depending on the amount of
memory in your machine, since you have in effect taken away (frozen) some of the memory that is
normally available. This can lead to a situation where thrashing occurs.
KLONDIKE and PAGES are closely related in terminology. So, you may find it helpful to review the
section on PAGES.
Capabilities
Program capabilities required include IA, BA, PM, DS and PH. User SM capability is required for
the FREEZE and THAW commands.
Usage
To run KLONDIKE either use the supplied UDCs or use a fully-qualified RUN command.
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:KLONDIKE
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Starts KLONDIKE, no parameters
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:COUNT <filename>
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Report on % of file in memory
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:FETCH <filename>
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Fetches a file into memory
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:RUN KLONDIKE.PUB.LPSTOOLS;INFO=“[commands]”
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NOTE filename can be either an MPE or POSIX filename.
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Command Summary
The following list provides a summary description of KLONDIKE commands that you can use to
quickly locate the command that suits the task at hand. Detailed information on each command is
provided in the next section.
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NOTE Portions of the command codes are printed in uppercase to denote the part of the command that KLONDIKE requires in order to distinguish one command from another. However, the commands themselves are not case-sensitive.
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Table 9.1 KLONDIKE commands
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Command Code
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Description
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COUNT
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Displays percentage of file in memory
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Exit
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Terminates the program
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FETCH
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Loads file into memory
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FREEZE
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Freezes file into memory
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Help
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Displays context-sensitive Help text
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Open
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Tests access to a file
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POST
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Writes file to disk
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SET/REset
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Enables or disables KLONDIKE options
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THAW
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Unfreeze file from memory (same as UNFREEZE)
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UNFREEZE
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Synonym for THAW
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Command Definitions
Listed below are detailed descriptions of each KLONDIKE commands. Syntax is provided in
some cases.
COUNT
The COUNT command has the following syntax:
COUNT <filename>
This command is used to count the number of pages of a file that are currently in memory and
then displays the results on the screen. It shows the percentage of a file in memory, as well as the
number of logical pages in memory. More information is displayed if the VERBOSE option is
selected.
FETCH
This command has the following syntax:
FETCH <filename> [[# <Pages | Bytes> | ALL]] [ <WAIT | NOWAIT> ]
The FETCH command opens the specified file and attempts to fetch the specified number of
pages (or bytes) into memory, starting at the beginning of the file.
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WAIT
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Instructs KLONDIKE to wait until all of the fetched pages are in memory before continuing.
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NOWAIT
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(default) Instructs KLONDIKE not to wait for all of the pages to be read into memory before continuing.
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NOTE Attempts to fetch more than 200 pages at a time will be broken into multiple smaller fetches automatically. This is done to prevent overloading the system with large requests.
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FREEZE
This command has the following syntax:
FREEZE <filename> [ALL | [# <Pages | Bytes>]]
The FREEZE command opens the specified file and attempts to freeze the file into memory. The
entire file will be frozen. A file frozen with the FREEZE command can be unfrozen with the THAW
command (or its synonym, UNFREEZE).
If a page of a file is frozen, and then updated, the data will NOT be posted to disk until sometime
after the file is THAWed or until a POST command is done.
OPEN
The OPEN command has the following syntax:
OPEN <filename>
This command is used to test the access to a file.
POST
This command has the following syntax:
POST <filename> [# <Pages | Bytes> | ALL] [<WAIT | NOWAIT>]
The POST command opens the specified file and attempts to post (force a write to disk) the
specified number of pages (or bytes) from memory, starting at the beginning of the file.
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WAIT
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(default) Instructs KLONDIKE to wait until all of the posted pages have been written to disk before continuing.
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NOWAIT
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Instructs KLONDIKE not to wait for all the disk writes to finish.
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SET | REset
The SET/RESET commands are used to specify the following options. Use these options to
enable or disable information-reporting features.
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PARTIAL
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SET sets the specified options to "true". RESET sets the standard options to "false".
If PARTIAL is true, KLONDIKE will allow partial file specification for some commands like: POST, FREEZE, and FETCH.
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TIMES
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SET sets the specified options to "true". RESET sets the standard options to "false".
If TIMES is true, KLONDIKE will report on information relating to how much cpu time & wall time were required to perform a task.
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VERBOSE
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SET sets the specified options to "true". RESET sets the standard options to "false".
If VERBOSE is true, KLONDIKE will report more information about a file in memory than it would if VERBOSE is false.
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THAW | UNFREEZE
These commands have the following syntax:
THAW <filename>
or
UNFREEZE <filename>
These two commands perform the exact same operation. What they do is open the specified file
and unfreeze the file from memory. The entire file will be unfrozen.
TOOLBOX STANDARDS
The ToolBox collections from Lund Performance Solutions have a uniform user interface. As a
result, in addition to the commands specific to each Toolbox tool, most tools allow the commands
described in
"TOOLBOX STANDARDS".
KLONDIKE Examples
Following are examples of the KLONDIKE tool.
Figure 9.1 shows how the COUNT command is used and what the output looks like:
Figure 9.1 COUNT Command
Figure 9.2 shows the effect of the Verbose and Times options when used with FETCH:
Figure 9.2 Verbose and Times Options
Figure 9.3 shows how to freeze a source file into memory:
Figure 9.3 Freezing a Source File into Memory
Figure 9.4 uses the CPUNT command to show that, indeed, the file has been frozen into memory.
Then, the THAW command is used to unfreeze the file. Finally, the COUNT command is used to
verify that the file was unfrozen:
Figure 9.4 COUNT and THAW Commands
KLONDIKE Error Messages
In the error messages that follow, "xxxx" refers to a number that is filled in at runtime by
KLONDIKE.
Table 9.2 KLONDIKE Error Messages
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Message
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Cause
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Action
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Attempted to fetch "xxxx" logical pages, which is illegal.
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User tried to fetch ZERO or less pages.
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KLONDIKE can only fetch a positive number of pages.
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Cannot freeze...file already has "xxxx" frozen pages.
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At least one page of the specified file is already frozen (KLONDIKE does not support partial file freezes).
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Determine who or what has frozen the file, unfreeze it, and then use KLONDIKE to freeze the file.
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File is already frozen.
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User tried to freeze a file that was previously frozen.
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KLONDIKE can only freeze a file once.
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File won’t fit in memory...won’t freeze it. Memory is only "xxxx" pages of 4,096 bytes.
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An attempt was made at freezing a file into memory that was larger than the amount of memory available on the system.
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Reduce the size of the file before freezing it.
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KLONDIKE will not freeze/thaw file in spaces $A or $B due to possible undesirable consequences.
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KLONDIKE was instructed to perform a freeze or thaw command into memory currently used by the operating system.
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No action is required, this is a warning only.
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Limiting fetch to "xxxx" logical pages (size of memory).
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User tried to fetch a file that is larger than the amount of memory on the machine.
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No action is required, this is a warning only.
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The file is not frozen...cannot unfreeze.
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User tried to unfreeze a file that was not frozen in the first place.
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Only previously frozen files can be unfrozen.
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