Disable cache memory on IA-32

Disable cache memory on IA-32

Hello,

I'm working on an university practice and I need to disable both levels of cache memory in order to show the difference between a system with and without cache.

My processor is an Intel Atom 1,6Ghz

Any suggestion to do it?

Thanks and sorry for my english,
em009

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It looks from here

http://www.tomshardware.com/reviews/intel-atom-cpu,1947-7.html

you can do it by forcing certain ACPI states

Ricardo Reis
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Quoting - em009
Hello,

I'm working on an university practice and I need to disable both levels of cache memory in order to show the difference between a system with and without cache.

My processor is an Intel Atom 1,6Ghz

Any suggestion to do it?

Thanks and sorry for my english,
em009

From hardware perspective, it is relatively simple. You should read section 10.5 of volume 3A of the manuals (see links provided by Mike Pearce).

But it may become a complex situation in the software stack. Do you expect an OS to provide a service to enable/disable cache on demand? I don't know if that exists (I doubt a commercial release version of OS would want to do that).

If you were in a position to engineer an OS service with such capability, it may become a significant effort toguarantee robust operation before and after you enable/disable caching. You may need to worry about the large number of processes that were already running, how will those pre-existing process handle cache coherency issues after cache is disabled?

It may happen the software stack you are testing is robust and/or simple enough with caching being disabled on demand. If so, you can wrap each workload you want to test with some scripts that invoke some utility that have ring 0 access privilege to fiddle with bit 30 of CR0.

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