Re: [gentoo-user] Limit number of cores used by emerge?

[Dale]

Paul Hartman wrote:
> On Fri, Sep 30, 2011 at 11:25 AM, Mark Knecht<markknecht@×××××.com>  wrote:
>> Hi,
>>    Is there a portage option that will limit the number of cores used
>> by emerge? For instance, in a chroot on a 12 core machine I want to
>> limit emerge to not using more than 3 cores?
>>
>>    If possible, I'd also like to limit the total disk bandwidth
>> consumption during emerge. For instance, when untarring a big file to
>> do the emerge at times the disk consumption gets to high and the
>> machine becomes laggy. Is there an option that addresses this?
>>
>>    These questions are mostly about being able to update a chroot
>> mid-day without other tasks slowing down too much. I don't care how
>> long the chroot really takes to get a huge emerge done, but rathe just
>> keeping the machine very responsive while it's happening. I already
>> use:
>>
>> MAKEOPTS="-j3"
>> PORTAGE_NICENESS="15"
>>
>> which helps (I think) but it doesn't totally address either of the issues above.
> If your MAKEOPTS is -j3 then it's not going to use more than 3 cores
> at a time but it will touch all 12 cores throughout the process
> because of the normal load balancing. If you want it to use only 3
> specific cores, you would need to set the processor affinity (usually
> done using the "taskset" command from sys-apps/util-linux).
>
> For the disk I/O you can set an ionice in your make.conf like:
> PORTAGE_IONICE_COMMAND="ionice -c 3 -p \${PID}"
>
> Salt to taste. :)
>
>

Well, this is interesting:

root@fireball # emerge -1av kate
ionice: bad prio class -3
  * PORTAGE_IONICE_COMMAND returned 1
  * See the make.conf(5) man page for PORTAGE_IONICE_COMMAND usage 
instructions.

When I went to copy this, I noticed it was commented out.  Now I see 
why.  What's up with this?

I bet Mark is going to get this too.

Dale

:-)  :-)