Re: Voyager subarchitecture for 2.5.46

[J.E.J. Bottomley]

[e-mail] said:
> We'd still need to go back and yank out the #ifdef CONFIG_X86_TSC'ed
> macros in profile.h and pksched.h or replace them w/ inlines that wrap
> the rdtsc calls w/ if(cpu_has_tsc && !tsc_disable) or some such line.

Actually, the best way to do this might be to vector the rdtsc calls through a 
function pointer (i.e. they return zero always if the TSC is disabled, or the 
TSC value if it's OK).  I think this might be better than checking the 
cpu_has_tsc flag in the code (well it's more expandable anyway, it won't be 
faster...)

When the TSC code is sorted out on a per cpu basis, consumers are probably 
going to expect rdtsc to return usable values whatever CPU it is called on, so 
vectoring the calls now may help this.

James