Pas un Geek en tant que tel

Problems with NetBSD/amd64 and est

It seems that there is quite a number of issues involved with implementing Speed Stepping on NetBSD/amd64, at least in version 4.0_BETA2.

At first I got a relatively easy set of steps that have to be performed in order to implement it:

• Move p[34]_get_bus_clock() from i386/i386/identcpu.c into x86/x86/intel_busclock.c (I used a single function merging p3 and p4).
• Move i386/i386/est.c into x86/x86.
• Update amd64/amd64/identcpu.c to run est_init().
• Update some required files like x86/conf/files.x86, etc.
• Update {amd64,i386}/conf/files.{amd64,i386}.

The first major one is the fact that support for cpu_features2 has been added only in NetBSD-current. However, threading in NetBSD-current is completely different than in 4.0_BETA2, which means that all packages have to be recompiled unless you want to have segmentation faults (bad system call) all over.

A temporary circumvention of this was to assume generally that speed stepping is supported (i.e. comment out the cpuid checks) if it is implied by the config.

However, it seems that simply calling est_init() as suggested in step 3 is not sufficient. There is still a requirement to call the *_get_bus_clock functions prior to calling est_init because est_init will assume that the system bus clock is unknown (Which is somewhat true). Thus, my current job seems to be to find out what is usually calling the cpu_info functions.