Bruce Evans <[EMAIL PROTECTED]> writes:
> K6-2's aren't really i586's and i586_bzero should never be used for
> them (generic bzero is faster),

Wrong. I fixed machdep.c to compute and print the bandwidth correctly:

des@des ~% egrep '(CPU|bzero)' /var/run/dmesg.boot
CPU: AMD-K6(tm) 3D processor (350.80-MHz 586-class CPU)
i586_bzero() bandwidth = 1056759 kBps
bzero() bandwidth = 124211 kBps

> i586_bzero gets used because negative bandwidths are significantly
> smaller than positive ones,

Uh, Bruce, we pick the method that gives the *highest* bandwidth, not
the lowest.

>                             so plain bzero is faster according to this
> message,

There you go contradicting yourself...

Anyway, the bug is not K6-specific - I guess the reason why we're only
seeing it on K6's is that they're the only 586-class CPUs that are
fast enough to still be in widespread use.

Except I just remembered I have a dual Pentium box I use for SMP work,
but haven't booted in several weeks... because it keeps crashing...
with a smashed stack.

Dag-Erling Smorgrav - [EMAIL PROTECTED]

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