Messages in this thread | | | Date | Thu, 1 Apr 1999 14:19:27 +0200 (CEST) | From | Andrea Arcangeli <> | Subject | Re: [patch] __volatile__ needed in get_cycles()? |
| |
On Tue, 30 Mar 1999, Andrea Arcangeli wrote:
>On Tue, 30 Mar 1999, Ingo Molnar wrote: > >>to have 'exact' get_cycles() we need both the compiler-level barrier, and >>both a pre- and post- rdtsc bus-level barrier, because both preceding and > >Are you really sure the post- rdtsc is needed? Sure theorically is needed, >but maybe the CPU isn't so smart as theory.
My guess was right, Intel never uses the post- cpuid. And Intel _always_ uses cpuid _before_ rdtsc.
- 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/
| |