Quoting <200006130929.KAA23144 at pancake.earlsfort.iol.ie>
by Nick Hilliard <nick at iol.ie>:
> > Let's see, are headers relatively short? Are they lots of little
> > files? Does that mean accessing headers is dominated by disk seeks.
> > What's one of the slowest operations on your system? Moving the disk
> > heads.
>> In most common source sets, after compiling the first few files, virtually
> all of the commonly used headers are cached by the OS, so most of the
> compile time is going to be CPU bound. A good way to see the bottleneck is
> to compile with "-pipe", which stops all of the intermediate file creation
> dreck (which accounts for most of the disk trashing during gcc compiles).
> "top" should in most cases reveal that the CPU is very busy.
It's still a lot of seeks to go and do at the start of the compile
though - on the other hand, if caching eliminates seek time accessing
headers as the reson for the 5x difference, how do you explain it? 8)
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