>> It's not correlating it to real time that's the problem. It's getting resceduled
>> inbetween calls that hurts. Take your example.
>>
>> rdtsc
>> mov %eax,%ebx
>> <- get rescheduled here
>> rdtsc
>>
>> Broken. May even take negative "time".
>
> Statistically irrelevant. When you have 100,000 samples all the
> pre-emption ones drop into the dud sample filter with IRQ disturbance
> and so on.
OK, so let's take a better example. People are (I think) mainly using rdtsc
to provide a monotonically increasing counter for database "transaction
order" stamping. I think that's really the case we're worried about.
M.
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This archive was generated by hypermail 2b29 : Sat Aug 31 2002 - 22:00:18 EST