Messages in this thread | ![/](/images/icornerl.gif) | | From | Steve Snyder <> | Subject | Re: Where to call L2 cache enabling code from? | Date | Fri, 14 Apr 2006 12:49:49 -0400 |
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On Friday 14 April 2006 11:46 am, Alan Cox wrote: > On Gwe, 2006-04-14 at 11:05 -0400, Steve Snyder wrote: > > I have a machine in which the BIOS does not enable the Pentium3's L2 > > cache at boot time. At what point in the kernel init process > > can/should I call the code to enable the cache? > > What part of the cache setup is not done correctly ? The mtrr registers > or other things ?
It's not that the kernel is failing in any respect. The BIOS simply does not enable the on-CPU L2 cache at power-on. (The machine originally shipped with a Pentium2, and doesn't know how to enable the L2 cache on the Pentium3 that is now running in it.)
I've got a small device driver that enables the L2 cache. It works fine when build as a module and loaded after booting has completed. My goal is to move the code into the kernel so that it is run early in the kernel init process. I expect that having the L2 cache go from "0KB" to 256KB will improve boot time greatly, as well as informing the kernel from the get-go of the true capabilities of this processor.
Getting the code into the kernel image is a no-brainer. But once it is built into the kernel, at what point should I call it?
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