Re: guile fibers - looking for adivce

[Aleix Conchillo Flaqué]

Hi Jan,

On Mon, Sep 7, 2020 at 7:56 AM Jan Wielkiewicz <
tona_kosmicznego_smiecia@interia.pl> wrote:

> Hi!
>
> Dnia 2020-09-05, o godz. 18:19:49
> Aleix Conchillo Flaqué <aconchillo@gmail.com> napisał(a):
>
> > Hi!
> >
> > On Sat, Sep 5, 2020 at 3:48 PM Jan Wielkiewicz <
> > tona_kosmicznego_smiecia@interia.pl> wrote:
> >
> > I believe sharing the same object by the two fibers defeats the
> > purpose of message passing, because with the way you are doing it you
> > find exactly the problem you are having and the only way to fix this
> > is by using mutexes. That is, you are trying to use fibers as you
> > would use regular threads sharing a resource. Instead, there should
> > probably be a main fiber (that holds the object) and send messages
> > (with the data needed from the object) to 2 other fibers (those would
> > be your methods A and B).
> I see, thank you for explanation. This allowed me to understand the
> problem doesn't lie in the way I was trying to implement my messaging
> through fibers, but rather in the way I was using GOOPS - my custom
> method for initializing slots called next-method after doing everything
> what caused some weird problems with allocation.
>
> Are threads and mutexes worth using, if there are fibers already?
> I know I'll have to learn this eventually, to fully master programming,
> but I'm not sure if there's a great advantage over fibers.
>
>
I don't think mixing threads and fibers is a good idea, so I would stick
with fibers. However, you might still want to use mutexes for certain
things.

This might be useful: https://github.com/golang/go/wiki/MutexOrChannel

As they say, sometimes you start over-using channels because it's fun, but
a mutex might just be simpler. So if you find yourself getting with too
many channels think if a mutex would be easier, and the other way around,
if using the mutex is getting too hairy try to think if a channel would be
easier.

I would suggest reading about Go routines and channels, since it's the same
as fibers and there's a lot of information out there.

> >
> > I haven't used fibers extensively, but I've used Go quite a bit which
> > follows the same pattern of channels and message passing and this is
> > how you would do it.
> >
> > Also, the fibers manual also suggests this approach:
> > https://github.com/wingo/fibers/wiki/Manual#33-mutation
> Yeah, I've read the manual like three times already, but Andy is
> somethimes writing sentences from outer space, including the GOOPS
> manual. This isn't the level of English I'm currently on.
> I guess I'll write some self-explaining examples of GOOPS after I fully
> understand it.
>
>
To be honest, I've never used GOOPS so things might be a bit more
complicated there, I don't know. But it sounds like you have two options:

- Create a fiber with the object and pass data from the object using
channels to other fibers. Then return data to the main fiber (or the fiber
that has the object) through a channel and update your object.
- Make the object global and have fibers that update the object. In this
case you would need to use mutexes.

Or maybe you find another way?

> That said, I might be wrong though.
> >
> > Hope this helps,
> >
> > Aleix
>
> Thanks for explanation, this made my thinking much cleaner. I can get
> back to experimenting now!
>
>
Cool, let us know!
Aleix