Re: [1/1] CBUS: new very fast (for insert operations) message bus based on kenel connector.

[Andrew Morton <akpm@osdl.org>]

Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
>
> On Thu, 2005-03-31 at 23:26 -0800, Andrew Morton wrote:
> > Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> > >
> > > > > +static int cbus_event_thread(void *data)
> > >  > > +{
> > >  > > +	int i, non_empty = 0, empty = 0;
> > >  > > +	struct cbus_event_container *c;
> > >  > > +
> > >  > > +	daemonize(cbus_name);
> > >  > > +	allow_signal(SIGTERM);
> > >  > > +	set_user_nice(current, 19);
> > >  > 
> > >  > Please use the kthread api for managing this thread.
> > >  > 
> > >  > Is a new kernel thread needed?
> > > 
> > >  Logic behind cbus is following: 
> > >  1. make insert operation return as soon as possible,
> > >  2. deferring actual message delivering to the safe time
> > > 
> > >  That thread does second point.
> > 
> > But does it need a new thread rather than using the existing keventd?
> 
> Yes, it is much cleaner [especially from performance tuning point] 
> to use own kernel thread than pospone all work to the queued work.
> 

Why?  Unless keventd is off doing something else (rare), it should be
exactly equivalent.  And if keventd _is_ off doing something else then that
will slow down this kernel thread too, of course.

Plus keventd is thread-per-cpu and quite possibly would be faster.