Re: [Nsock] Scalable event handling

[Henri Doreau <henri.doreau () gmail com>]

2013/8/7 David Fifield <david () bamsoftware com>:
> On Thu, Jul 25, 2013 at 10:31:03PM +0200, Henri Doreau wrote:
> > 2013/7/25 David Fifield <david () bamsoftware com>:
> > > +   gh_lnode_t nodeq;
> > > +   gh_lnode_t nodeq2; /* used for pcap events */
> > >
> > > Can you elaborate on how nodeq and nodeq2 work? From what I understand,
> > > nodeq2 is used for pcap-related events and nodeq is used for other kinds
> > > of events. Why do these need to be separate? I wonder if there is a more
> > > orthogonal way to do it. first_ev_next taking a nodeq2 parameter to
> > > choose which list to work on is a little strange.
> > That's it nodeq is for everything but pcap and nodeq2 is for pcap
> > only. The thing is that nsock has this strange "BSD hack mode" where
> > pcap events are added to both "read" and "pcap_read" event lists. This
> > requires a second gh_lnode_t handle. Having it always (not only in
> > BSD_HACK_MODE) used for "pcap_read" events makes the code lighter.
> >
> > The current gh_list implementation hides it a bit, but It's been there
> > for a while. I'm not fond of it either I have to say, but I'm planning
> > to change these linked lists to something else (probably a unique red
> > black tree, I'm still experimenting and benchmarking at the moment).
> > Making the BSD hack mode less intrusive will be one of my goals then.
> >
> > One thing I could do in order to avoid having an extra gh_lnode_t (=
> > two pointers) per structure when not in BSD_HACK_MODE is to add inline
> > helpers or play with macros like:
> >
> > #ifdef BSD_HACK_MODE
> >   gh_lnode_t nodeq2;
> > #else
> > #define nodeq2 nodeq
> > #endif
>
> I don't want you to do any tricks to change the structures. I'm not
> worried about struct sizes. Do you think the member name should be
> nodeq_bsd_hack or something like that? That would be enough of a clue as
> to what it's for.
I admit that nodeq and nodeq2 is cryptic. Let's say nodeq_io and
nodeq_pcap, and add a comment about how they're used. nodeq_bsd_hack
suggests that it's only used when in BSD hack mode, which is
misleading.

> Please go ahead and merge this patch when you are ready.
>
> David Fifield
Sure. I first need to figure out why you get test failures. I suspect
it has more to do with the test than with nsock but I want to make
sure and fix it. Let me know if you see something new.

Regards

-- 
Henri
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