Re: Sched_autogroup and niced processes

From: Mike Galbraith
Date: Fri May 13 2011 - 09:13:35 EST


On Fri, 2011-05-13 at 12:04 +0200, Ingo Molnar wrote:

> Still, the other important problem is that we still seem to have a bug, even
> with the cgroup set to low prio seti@home is sucking up CPU resources ...

I don't see how. Other than the expected nice 19 overrun when nice 0
group blocks, it works fine on my little Q6600 box.

time make -j4 vmlinux (cache hot)

real 2m22.996s
user 7m6.887s
sys 0m48.999s

echo 0 > sched_autogroup_enabled

time make -j4 vmlinux

real 2m17.052s (darn, no free lunch)
user 7m5.483s
sys 0m49.415s

echo 1 > sched_autogroup_enabled

simultaneous massive_intr 8 9999 in nice 19 autogroup and
time make -j4 vmlinux in a nice 0 autogroup

real 2m30.863s
user 7m5.363s
sys 0m47.359s

142.996/150.863 = .947 (a tad low)

repeat with 2 kbuild tasks/core to cut nice 0 group's idle time

time make -j8 vmlinux

real 2m24.925s
user 7m16.327s
sys 0m50.807s

142.996/144.925 = .986 (all better)

-Mike

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