Ako bolo uz spomenute intel procesory nemaju uplne viazane Rdtsc na pocet vykonanych instrukcii.Zalezi od modelu. (http://download.intel.com/design/processor/manuals/248966.pdf)
Processor families increment the time-stamp counter differently:
• For Pentium M processors (family [06H], models [09H, 0DH]); for Pentium 4
processors, Intel Xeon processors (family [0FH], models [00H, 01H, or 02H]);
and for P6 family processors: the time-stamp counter increments with every
internal processor clock cycle.
The internal processor clock cycle is determined by the current core-clock to bus-
clock ratio. Intel® SpeedStep® technology transitions may also impact the
processor clock.
• For Pentium 4 processors, Intel Xeon processors (family [0FH], models [03H and
higher]); for Intel Core Solo and Intel Core Duo processors (family [06H], model
[0EH]); for the Intel Xeon processor 5100 series and Intel Core 2 Duo processors
(family [06H], model [0FH]); for Intel Core 2 and Intel Xeon processors (family
[06H], display_model [17H]); for Intel Atom processors (family [06H],
display_model [1CH]): the time-stamp counter increments at a constant rate.
That rate may be set by the maximum core-clock to bus-clock ratio of the
processor or may be set by the maximum resolved frequency at which the
processor is booted. The maximum resolved frequency may differ from the
maximum qualified frequency of the processor, see Section 18.20.5 for more
detail.
The specific processor configuration determines the behavior. Constant TSC
behavior ensures that the duration of each clock tick is uniform and supports the
use of the TSC as a wall clock timer even if the processor core changes frequency.
This is the architectural behavior moving forward.Vol. 3 18-43
To determine average processor clock frequency, Intel recommends
the use of EMON logic to count processor core clocks over the period
of time for which the average is required. See Section 18.20,
“Counting Clocks,” and Appendix A, “Performance-Monitoring Events,” for more information
Pravdepodobne tie vysledky z Intelov budu asi blbe.
