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Re: Faster compilation speed: cache behavior (Mike Stump)  wrote on 21.08.02 in <>:

> On Tuesday, August 20, 2002, at 11:40 PM, Kai Henningsen wrote:
> > (Mike Stump)  wrote on 20.08.02 in
> > <>:
> >
> >> On Tuesday, August 20, 2002, at 03:45 PM, Geoff Keating wrote:
> >>> Does Apple's memset use dcbz?  I'm curious why memset should cause
> >>> any
> >>> cache misses at all.
> >>
> >> The symbols mentioned are just one possible value of the pc within the
> >> millisecond (by default) when the sample was taken.   The sample
> >
> > Uh, I thought they were the exact instruction that caused the cache
> > miss,
> > and this particular profile was *not* based on timed samples?!
> I am very new to  all the counters and their semantics and what all the
> numbers mean.  However, from my limited understanding, I don't believe
> this is the case.  Was your understanding obtained by reading the chip
> docs about the counters?  By experimenting with them heavily?

By reading what Matt wrote about it, at the start of the thread. He  
claimed that he first obtained a list of the instructions causing cache  
misses, and then figured out where they were belonged.

I have no idea if that is true, but when what you claim and what he claims  
is so drastically different, confusion is only to be expected.

MfG Kai

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