incorrect usleep/select delays with HZ > 2500

[Garrett Wollman]

In article <20090906155154.GA8283 at onelab2.iet.unipi.it> you write:
>(this problem seems to affect both current and -stable,
>so let's see if here i have better luck)
>
>I just noticed [Note 1,2] that when setting HZ > 2500 (even if it is
>an exact divisor of the APIC/CPU clock) there is a significant
>drift between the delays generated by usleep()/select() and those
>computed by gettimeofday().  In other words, the error grows with
>the amount of delay requested.

If I may be so bold as to suggest: if you think you want HZ > 1000,
you're probably wrong.

-GAWollman
-- 
Garrett A. Wollman    | What intellectual phenomenon can be older, or more oft
wollman at bimajority.org| repeated, than the story of a large research program
Opinions not shared by| that impaled itself upon a false central assumption
my employers.         | accepted by all practitioners? - S.J. Gould, 1993