[fpc-devel] Threads and alot of crap

[Daniël Mantione]

Op Tue, 17 Oct 2006, schreef Jonas Maebe:

> 
> On 17 okt 2006, at 09:25, Daniël Mantione wrote:
> 
> > If I compare my implementation of the Chameneos benchmark with the one
> > from Marc (which uses Pthreads directly), mine is about two times slower.
> > This is propably caused that our thread functions often require multiple
> > Pthread calls,
> 
> Where? I only see this in starting/initialising/stopping/destructing things.
> The actual locking etc use one pthread call in all cases afaics. Of course,
> starting a Pascal thread requires initialising all the threadvars etc, but
> that is not going to change if you use something else than pthreads.

For example:

procedure intRTLEventSetEvent(AEvent: PRTLEvent);
var p:pintrtlevent;

begin
  p:=pintrtlevent(aevent);
  pthread_mutex_lock(@p^.mutex);
  pthread_cond_signal(@p^.condvar);
  pthread_mutex_unlock(@p^.mutex);
end;

procedure intRTLEventStartWait(AEvent: PRTLEvent);
var p:pintrtlevent;

begin
  p:=pintrtlevent(aevent);
  pthread_mutex_lock(@p^.mutex);
end;

procedure intRTLEventWaitFor(AEvent: PRTLEvent);
var p:pintrtlevent;

begin
  p:=pintrtlevent(aevent);
  pthread_cond_wait(@p^.condvar, @p^.mutex);
  pthread_mutex_unlock(@p^.mutex);
end;


I'm not 100% sure yet, but I believe you can implement a set-event with a
FUTEX_WAKE, and a waitfor with an unconditional FUTEX_WAIT, which would 
mean a lot less calls.

Daniël