Messages in this thread | | | Date | Wed, 10 Nov 1999 03:30:32 -0500 (EST) | From | "Mike A. Harris" <> | Subject | How to determine what portion of memory is cached? |
| |
Is there a way in the kernel startup code (or anywhere in kernel for that matter) to determine what portions of physical system RAM are cached?
I mean, other than manually benchmark testing memory regions for speed, does the BIOS return this info?
If there is no standards answer of "yes", then do SOME machines have a way of determining at runtime what areas of memory are cached?
If there is no standard or nonstandard way of polling the BIOS or chipset to determine this, then what would be an easy way to manually bench memory to determine if it is cached (assuming that some memory IS cached that is).
On boards where it is possible, I want to have the kernel autodetect the memory regions which are NOT cached (or that are cached - either is fine as one can be determined from the other), and display a message on the screen at boot, giving a list of uncached memory regions. This is to include any regions marked uncacheable by the BIOS, as well as memory that cannot be cached due to chipset limitations (like boards that will take 512Mb of RAM, but only cache up to 64Mb for example).
Any pointers as to where to look in the kernel source for something like this, or any code examples that someone might have would be greatly appreciated. I'm looking at setup.c but have been so far unable to find anything.
Thanks in advance. TTYL
-- Mike A. Harris Linux advocate Computer Consultant GNU advocate Capslock Consulting Open Source advocate
Join the FreeMWare project - the goal to produce a FREE program in which you can run Windows 95/98/NT, and other operating systems.
http://www.freemware.org
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |