svn commit: r252032 - head/sys/amd64/include

[Dmitry Morozovsky]

On Tue, 25 Jun 2013, Konstantin Belousov wrote:

> > > Updates to the counter cannot be done from the interrupt context.
> > 
> > This is fragile, however.  It prevents using counters for things like
> > counting interrupts.  Most interrupt counting is now done directlyly
> > and doesn't use PCPU_INC().  i386/i386 has just 1 use of PCPU_INC().
> > It is to count traps in machdep.c.  Traps include nonmaskable
> > interrupts.  Even hard-disabling of interrupts doesn't prevent these.
> > Otherwise, PCPU is used mainly for vm counters.  E.g., for pagefaults.
> > Now the trap is not an interrupt, so it shouldn't occur in the middle
> > of the counter update and the PCPU_INC() can safely be replaced by
> > a counter, but this is not clear.
> Traps are not performance critical in the sense that there is no need to count
> up to 1-10G traps per second.  Anyway, as Gleb said, there is no point in
> optimizing the i386 kernel.  

Hmm, don't we count semi-embedded routers? Or, do we think they are either 
amd64 or arm/mips?

[snip all the rest]


-- 
Sincerely,
D.Marck                                     [DM5020, MCK-RIPE, DM3-RIPN]
[ FreeBSD committer:                                 marck at FreeBSD.org ]
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*** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck at rinet.ru ***
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