Mark Haney wrote:
> I've been extremely busy lately and have let my updates get way behind.
> Part of that is my need to keep kde-libs-3.5 on my system for K3b, etc,
> part of that is just too much else to do.
> 
> The problem I've encountered is when I try to do an update while I'm
> working, my system can slow to a crawl, on a big compile usually.  I've
> tried using nice to manage how much CPU the compile gets so I can
> function while it's building, but it's killing the output so I can't see
> what's going on.
> 
> Is there another way to use nice, or to fix that problem?  Or another
> way to manage CPU usage during an emerge?

You can also "ionice" portage in addition to just "nice".  I'm using 
"nice 19" and "ionice idle".  To achieve this, in make.conf:

   PORTAGE_NICENESS=19
   PORTAGE_IONICE_COMMAND="ionice -c 3 -p \${PID}"

On my system, "ionice" makes a bigger difference than "nice" (I'd rather 
say that "nice" doesn't result in any noticeable effect at all.)

"man ionice" will give you some info about it does.  In short, it does 
for I/O operations what "nice" does for CPU time.