Messages in this thread | | | Date | Mon, 29 Mar 1999 13:56:40 +0200 (CEST) | From | Andrea Arcangeli <> | Subject | Re: [patch] __volatile__ needed in get_cycles()? |
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On Mon, 29 Mar 1999, Tigran Aivazian wrote:
>which would enforce "Von Neumann execution stream", e.g. by doing CPUID
What is a Von Neumann execution stream? ;)
>first, but one needs to measure the combined cpuid+rdtsc overhead and
Why you need CPUID?
If you need to know some features from the CPU you probably want to use the information we grabbed at boot time in the current_cpu_data struct.
About the volatile thing the reason I thought it's not needed is that we care that rdtsc is run always at the same offset of code. We care only about the _delta_ between the two rdtsc. So basically I seen not using __volatile__ as a feature. Comments?
Andrea Arcangeli
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