IoPageLockLimit / System Cache

[Hernan Marsili]

Does anyone know the relation between the IoPageLockLimit value and the
"System Cache". When I incresed the value of the IoPageLockLimit, the system
cache dramaticaly decreases.

Any suggestion for performance optimization? Should I leave windows manage
the system cache?

Regards, Hernán.

[Jeff Phillips]

Easiest way to modify these settings is with a 3rd party program like
Tweak-XP or X-Setup.... They also contain explinations for these values and
is probably the safest way to modify and tune XP performance since they
either create a restore point or a reg snapshot before they modify settings.

"Hernan Marsili" <hmar...@usa.net> wrote in message
news:u8uIVn7eBHA.1432@tkmsftngp04...

[Hernan Marsili]

Jeff,

Thank you for your answer. I did use Tweak-XP but my question was intented
to understand the relation between this two values. Any idea?

HM.-

"Jeff Phillips" <psyk...@geekextreme.com> wrote in message
news:OQz7EJBfBHA.2428@tkmsftngp05...

[Jeff Phillips]

IOPageLockLimit value determines what algorithym XP will use to determine
the number of pages that are locked into system RAM before being paged to
disk.

(Q121965)"By default, this limit is 0, which indicates to the system that it
should use a built-in algorithm to determine the amount of memory. You can
change this value to indicate the number of bytes that can be used for
MmProbeAndLockPages."

you can also look at (Q102985)

Here's the full text of Q121695;
SUMMARY
When using MmProbeAndLockPages, you need to remember that there is a limit
to the amount of memory that can be locked down by MmProbeAndLockPages. The
amount of memory is normally determined by the computer system at boot time.
However, if you need to probe and lock more memory than is being allowed,
there is a registry parameter that you can configure to allow you to
determine the amount of memory available to probe and lock.

A key named IoPageLockLimit is located in
HKEY_LOCAL_MACHINE\CurrentControlSet\Control\Session Manager\Memory
Management. By default, this limit is 0, which indicates to the system that
it should use a built-in algorithm to determine the amount of memory. You
can change this value to indicate the number of bytes that can be used for
MmProbeAndLockPages.

NOTE: Be careful when changing this value. The default value computed by the
system when IoPageLockLimit is 0 is tuned specifically for system
performance. Allowing the system to lock down more memory can have a
detrimental effect on system performance.

Additional query words : NT DDK kernel mode memory
Keywords :
Issue type : kbhowto

IMHO, you should always let Windows manage the System Cache according to the
two settings (application performance or system performance) -- you'll get
alot more mileage managing the paging process and the way that the Executive
process deals with it's memory usage than tweaking the setting beyond what's
in TweakXP.... If you come up with some nifty tidbit that enhances
performance contrary to this, please share!

=)

[Hernan Marsili]

Thank you. A rocky question... what happened if I configure certain value on
the registry, for example, IoPageLockLimit with 4096kb and then I DELETE the
key... Windows will assume the default value? (512k) ????

Thank you.

"Jeff Phillips" <psyk...@geekextreme.com> wrote in message

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