Re: [PATCH] netfilter: conntrack: use power efficient workqueue

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Mon, Nov 06, 2017 at 03:31:55PM +0100, Pablo Neira Ayuso wrote:
> On Thu, 2 Nov 2017 15:16:07 +0100 Vincent Guittot <vincent.guittot@linaro.org> wrote:
> > conntrack uses the bounded system_long_wq workqueue for its works that
> > don't have to run on the cpu they have been queued.  Using bounded
> > workqueue prevents the scheduler to make smart decision about the best
> > place to schedule the work.
> >
> > This patch replaces system_long_wq with system_power_efficient_wq.
> > the work stays bounded to a cpu by default unless the
> > CONFIG_WQ_POWER_EFFICIENT is enable. In the latter case, the work can
> > be scheduled on the best cpu from a power or a performance point of
> > view.
> 
> Applied, thanks.

I'm stepping back. According to what I'm reading
system_power_efficient_wq becomes system_wq when disabled, which is
not semantically the same as system_long_wq that we have now.

My concern is that the conntrack garbage collector may run for quite a
bit of time. Did you test this with a large conntrack table full of
entries?

Thanks.