Re: [Nsock] Scalable event handling

[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.

Please go ahead and merge this patch when you are ready.

David Fifield
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