Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 4:05 PM, Paul Hartman paul.hartman+gen...@gmail.com wrote: On Fri, Sep 30, 2011 at 5:47 PM, Mark Knecht markkne...@gmail.com wrote: OK, my bad for confusing the two. Currently make.conf in the chroot says: MAKEOPTS=-j3 and when I run emerge in the chroot it's typically emerge -DuN -j2 @world so I think that's about right, or would hope it is anyway. If you see a problem please let me know. The -j2 on emerge means it'll run 2 makes at once, and each make is getting -j3, so it'll use (up to) 6 cores at once. You probably want to just stop using -j option for emerge entirely and stick to the MAKEOPTS one. I wondered about that. Thanks. It's back to single packages at a time in the chroot. Cheers, Mark
[gentoo-user] Limit number of cores used by emerge?
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. Thanks, Mark
Re: [gentoo-user] Limit number of cores used by emerge?
Mark Knecht 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.
Thanks,
Mark
This may help:
PORTAGE_IONICE_COMMAND=ionice -c -3 -p \${PID}
Make sure you have util-linux installed since it has the ionice
command. I think you have to have it enabled in the kernel as well.
I'm not certain tho.
On my machine, even if I tell emerge to only do one job at a time, it
still staggers around the cores. I guess it makes the CPU heat spread
out evenly or something.
Hope that helps.
Dale
:-) :-)
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 12:55 PM, Dale rdalek1...@gmail.com wrote: Mark Knecht wrote: 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? On my machine, even if I tell emerge to only do one job at a time, it still staggers around the cores. I guess it makes the CPU heat spread out evenly or something. Difference between number of cores and which cores...-j1 should mean it won't use more than one core at a time, but it might switch around which core when the process gets descheduled and brought back. (Or when a process ends and another is spawned) -- :wq
Re: [gentoo-user] Limit number of cores used by emerge?
Michael Mol wrote: On Fri, Sep 30, 2011 at 12:55 PM, Dalerdalek1...@gmail.com wrote: Mark Knecht wrote: 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? On my machine, even if I tell emerge to only do one job at a time, it still staggers around the cores. I guess it makes the CPU heat spread out evenly or something. Difference between number of cores and which cores...-j1 should mean it won't use more than one core at a time, but it might switch around which core when the process gets descheduled and brought back. (Or when a process ends and another is spawned) I'm not certain of why but when I am doing anything CPU intensive, it bounces from one core to another every 15 or 20 seconds. I just assume it is a heat thing. I created a 6Gb tarball the other day that took quite a while. It looks like a bar graph equalizer with the processes bouncing around from core to core. I just thought it worth mentioning in case the OP didn't realize this. Heck, I have had this happen with Seamonkey and I don't think it even sees multiple cores or anything. I also forgot to mention that the IONICE line goes in make.conf if you want it to be used each time. Dale :-) :-)
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 11:25 AM, Mark Knecht markkne...@gmail.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. :)
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 10:28 AM, Paul Hartman
paul.hartman+gen...@gmail.com wrote:
On Fri, Sep 30, 2011 at 11:25 AM, Mark Knecht markkne...@gmail.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. :)
Thanks to all who have answered so far. I'll give the ionice command a
try immediately. I'll try to address my view of other comments in a
single post to keep the traffic down.
My experience with -j3 is not that it limits emerge to 3 CPU cores but
rather it limits emerge to running 3 _jobs_. There's a big difference.
1 job can use 12 cores if gcc spawns a lot of stuff in parallel, which
in my experience it does. It's this parallel spawn running up to 12
cores in use which causes the machine to lag. Even when not setting
the -j option at all which results in a single package being emerged
at one time, I often use 6-12 cores in use for short periods of time
as gcc builds that package. This is completely appropriate for the
host machine. When I do updates I want them to get done ASAP. On the
other hand, for a chroot it's too much power.
Concerning which core is used, I don't care.
Concerning the 'bouncing around' aspect of multi-core processors,
that's primarily a CPU function of where it has cached data code as
well as thermal management on chip. Internal hardware is generally
controlling what CPU gets used for what as far as I know. However even
a single emerge job (1 package being emerged) could move around from
core to core depending on what work is getting done. It's
understandable that a driver might be fundamentally associated with a
specific core's immediate L1 or L2 cache, whereas the emerge job
itself could be using other cores.
Of course, everything above is just my limited understanding of what
the hardware is doing and could be completely wrong.
Thanks,
Mark
Re: [gentoo-user] Limit number of cores used by emerge?
Paul Hartman wrote:
On Fri, Sep 30, 2011 at 11:25 AM, Mark Knechtmarkkne...@gmail.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
:-) :-)
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 1:41 PM, Dale rdalek1...@gmail.com wrote: 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. I bet you have a typo on your ionice command in make.conf. :) You should have -c 3 not -c -3 as I will guess you might have from that error message about priority class -3.
Re: [gentoo-user] Limit number of cores used by emerge?
Paul Hartman wrote:
On Fri, Sep 30, 2011 at 1:41 PM, Dalerdalek1...@gmail.com wrote:
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.
I bet you have a typo on your ionice command in make.conf. :)
You should have -c 3 not -c -3 as I will guess you might have from
that error message about priority class -3.
BINGO !! That was it. Mark, if you copy mine, remove the - in front of
the 3. Aw heck,
PORTAGE_IONICE_COMMAND=ionice -c 3 -p \${PID}
That one works mucho better. ;-)
Thanks Paul for seeing my boo boo. Thing is, I copied and pasted that
from somewhere.
Dale
:-) :-)
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, 30 Sep 2011 11:15:16 -0700, Mark Knecht wrote: 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). My experience with -j3 is not that it limits emerge to 3 CPU cores but rather it limits emerge to running 3 _jobs_. There's a big difference. 1 job can use 12 cores if gcc spawns a lot of stuff in parallel, which in my experience it does. It's this parallel spawn running up to 12 cores in use which causes the machine to lag. Even when not setting the -j option at all which results in a single package being emerged at one time, I often use 6-12 cores in use for short periods of time as gcc builds that package. That's the --jobs option for emerge. The suggestion was to set the -J option in MAKEOPTS, which tells GCC how many compilation threads to run at once, and that's one core per thread. You'll also need to set -j 1 for emerge, which will also reduce the amount of disk thrashing that can happen when two package hit unpack at the same time. -- Neil Bothwick If at first you don't succeed, skydiving is not for you. signature.asc Description: PGP signature
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 3:09 PM, Neil Bothwick n...@digimed.co.uk wrote: On Fri, 30 Sep 2011 11:15:16 -0700, Mark Knecht wrote: 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). My experience with -j3 is not that it limits emerge to 3 CPU cores but rather it limits emerge to running 3 _jobs_. There's a big difference. 1 job can use 12 cores if gcc spawns a lot of stuff in parallel, which in my experience it does. It's this parallel spawn running up to 12 cores in use which causes the machine to lag. Even when not setting the -j option at all which results in a single package being emerged at one time, I often use 6-12 cores in use for short periods of time as gcc builds that package. That's the --jobs option for emerge. The suggestion was to set the -J option in MAKEOPTS, which tells GCC how many compilation threads to run at once, and that's one core per thread. You'll also need to set -j 1 for emerge, which will also reduce the amount of disk thrashing that can happen when two package hit unpack at the same time. -- Neil Bothwick OK, my bad for confusing the two. Currently make.conf in the chroot says: MAKEOPTS=-j3 and when I run emerge in the chroot it's typically emerge -DuN -j2 @world so I think that's about right, or would hope it is anyway. If you see a problem please let me know. I'll add the ionice stuff this weekend and see how it goes. Thanks, Mark
Re: [gentoo-user] Limit number of cores used by emerge?
On Fri, Sep 30, 2011 at 5:47 PM, Mark Knecht markkne...@gmail.com wrote: OK, my bad for confusing the two. Currently make.conf in the chroot says: MAKEOPTS=-j3 and when I run emerge in the chroot it's typically emerge -DuN -j2 @world so I think that's about right, or would hope it is anyway. If you see a problem please let me know. The -j2 on emerge means it'll run 2 makes at once, and each make is getting -j3, so it'll use (up to) 6 cores at once. You probably want to just stop using -j option for emerge entirely and stick to the MAKEOPTS one.
