On Fri, Dec 09, 2016 at 08:18:45PM +0100, Pavlos Parissis wrote:
> On 9 December 2016 at 20:07, Apollon Oikonomopoulos <[email protected]>
> wrote:
(...)
> >> > I wonder if a `per-process' keyword would make sense here. I find
> >> >
> >> > bind :443 ssl .... per-process
> >> >
> >> > more concise than 15 or 20 individual bind lines. This would have the
> >> > same effect as N bind lines, one for each process in the bind-process
> >> > list.
(...)
> Indeed, that would be nice. I guess it isn't big issue as most of the
> people use a configuration management tool, which does the expansion.
I find that this is a very good idea. We need to be careful when implementing
it because it will definitely come with problematic cases, but the idea is
good. In fact, Manu suggested to me in private that using multiple bind
lines is not convenient for him because he loads tons of certificates and
it would require him to load them multiple times (takes more time, eats more
memory). Something like the above, if properly designed, would solve that as
well.
I think we have to think a bit about a reusable implementation because we
also need to implement something comparable for the DNS resolvers so that
there's a per-process socket. In the end I suspect that we'll end up having
a list of FDs instead of a single FD for each process.
Also recently I noted that the cpu-map statement is boring when you deal
with many processes, and even more when you want to experiment with
different nbproc values because often you have to comment out many lines
and try again with many new ones. Most often we just want to have one
CPU for one process and they have to follow a regular pattern, eg +1 for
the process means +1 for the CPU. But sometimes due to hyperthreading or
NUMA you may need to use +2 or +8. Thus I was thinking we could have an
automatic cpu-set value by using something more or less like this :
cpu-map 1-10 2+1
cpu-map 11-20 16+1
This would do the same as this :
cpu-map 1 2
cpu-map 2 3
cpu-map 3 4
...
cpu-map 10 11
cpu-map 11 16
...
cpu-map 20 25
We could also have this :
cpu-map 1-10 2+2
equivalent to :
cpu-map 1 2
cpu-map 2 4
cpu-map 3 6
cpu-map 4 8
...
And maybe we can add a "/X" statement to apply a modulo after the increment
and limit the number of CPUs used in the loop :
cpu-map 1-7 2+8/14
equivalent to :
cpu-map 1 2
cpu-map 2 10
cpu-map 3 4
cpu-map 4 12
cpu-map 5 6
cpu-map 6 14
cpu-map 7 8
This can be useful to automatically enable use of some NUMA nodes or not
depending on the nbproc value.
Maybe others have other ideas, they're welcome.
Cheers,
Willy
