TSC Timer "Quality" ?

Peter B pb at ludd.ltu.se
Fri Oct 14 13:07:34 PDT 2005


>
>Intel pentium cpu timer tsc:
>  'Timecounter "TSC" frequency X Hz quality Y' (from dmesg)
>
>What is the definition of "quality" ..?
>
>
>I have looked briefly in the /usr/src/sys/i386/i386/tsc.c sourcefile and
>the intel-celeron datasheet. Without finding anything useful.
>
>   From src/sys/sys/timetc.h:
>        54         int                     tc_quality;
>        55                 /*
>        56                  * Used to determine if this timecounter is
>   better than
>        57                  * another timecounter higher means better.
>   Negative
>        58                  * means "only use at explicit request".
>        59                  */
>   As far as I understand this, it is used internally only.
>   Regards
>   Björn

Hmm.. should have looked into the header =)
Guess I'll have to check the clock circuit physicaly..

The reason for asking is to explore a way to sample signals asynchronously.
But useing timestamps to calculate how it looks when sampled synchronously.
Thus avoiding the need for fifo circuitry.


Btw, avoid html encoded email pls.


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