[lfs-support] Final GCC Compile Weirdness - 1 Time? No, 2 nd Time? Perfect!

Matijn Woudt tijnema at gmail.com
Mon Jan 9 11:26:42 PST 2012


On Mon, Jan 9, 2012 at 4:57 PM,  <jasonpsage at jegas.com> wrote:
> Now, I wouldn't care that much except even running on a DEDICATED 32bit
> Linux (Slackware 13.37) with MAKEFLAGS set to EIGHT to use all CORES...
> it takes a while... So running the procedure twice is time
> consuming.. We're talking hours on a new i7 DELL XPS Studio (Quad Core
> with hyper-threading - its like having EIGHT CPU)

You should know better that hyper-threading is far from having 8 real
cores, you're compile time is probably nearly the same as with
hyper-threading disabled.

>
> So - Should I be worried? Does anyone have a clue how that could happen?
> Does Anyone want to see the Script
> that I run TWICE (and it has all the clean up etc and source code
> un-tarring)?
>
> Any help is always appreciated! Thank You...
>
> --Jason

Did you read section 4.5 "About SBUs"?[1]. It says that average
compile time is measured depending on how long it took you to compile
the very first package. GCC in chapter 6 (6.17) says: "Approximate
build time: 47 SBU", so if your binutils package took 10 minutes, your
GCC compilation would take about 47*10 = 470 minutes, almost 8 hours.

Matijn

[1] http://www.linuxfromscratch.org/lfs/view/stable/chapter04/aboutsbus.html



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