On Mon, Dec 4, 2017 at 10:11 PM, taii...@gmx.com <taii...@gmx.com> wrote:
> On my 16 core opteron I have to do -j32 or sometimes -j64 to be using
> everything all the time, is this normal? If I don't do this it won't be
> pegged at 100% all the time.
>
I use a ramdisk and anything over -j${NCPU} (incl. hyperthreaded
cores) causes performance degradation in general due mainly to the
compiling step. For some package sets I have noticed that higher build
parallelism helps due to some ebuild steps not being easily
parallelizable.
> I assume using a ramdisk would help with this? I wouldn't want to do a SSD
> as I assume it would excessively wear by doing compiles.
>
It should. While builds on an SSD will wear the SSD, comparing the
write volume to the expected drive lifetime will tell you the true
impact. It is (if I remember) still relatively small.
Cheers,
R0b0t1
