This is the mail archive of the libc-alpha@sourceware.org mailing list for the glibc project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: [PATCH] hp-timing for ppc32/64


Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote on 11/14/2005 
02:44:22 PM:

> 
> How do they implement hp timing on, let's say, x86 where they have all
> sort of different time sources depending on the processor they are
> running on ? They don't have access to dl_hwcap ?
> 

On x86 they only implement hp-timing on i686 and newer based on the "Time 
Stamp Counter" and the "read time-stamp counter" instruction. Since they 
only have one "kind" of timebase they don't need to access dl_hwcap in 
hp-timing. This is also true for alpha, ia64, sparc, X86_64 and powerpc64. 
It would be true for ppc32 except for the 601 and 403 chips ...

The whole idea of hp-timing is that is fast, simple, and inline code. It 
is not a general purpose clock. It must also work in the restricted 
environment of the dynamic loader itself, like before and the durring the 
time the loader is relocating its self!

Steven J. Munroe
Linux on Power Toolchain Architect
IBM Corporation, Linux Technology Center


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]