Re: [PATCH 1/9] Remove parent field in cpuacct cgroup

[Glauber Costa]

On 09/19/2011 03:35 PM, Peter Zijlstra wrote:
> On Mon, 2011-09-19 at 13:30 -0300, Glauber Costa wrote:
> > For cpuusage, I am not sure this optimization is a valid one
>
> I was talking about cpuusage, cpuacct_charge() is called for every
> ctxsw/tick.

I am not touching it right now.

> But even for cpuacct tick stuff, wouldn't you need to sum all your child
> cgroups to update the current cgroup? and that up the whole tree?

Of course I would. But as I said, it does not need to be done every 
tick, in case it poses such a cacheline mayhem as you fear.

Since we'll only really need those values when someone reads it - which 
is a far less frequent operation than the tick resolution - and when a 
cgroup is destroyed - even less frequent operation - it should work well.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/