bug#16594: 24.3.50; very slow redraw when resizing windows horizontally

[Darren Hoo]

Paul Eggert <eggert@cs.ucla.edu> writes:

> While we're waiting for more info, attached is another shot in the
> dark; does this work around the problem?

Thanks, Paul

I've tried the patch but with no luck.

Whenever the hiccup occurs, it is always accompanied by two SIGALARMS
like this (Proccess... is the debugger output, others are my debug
outputs): 

Process 80842 stopped and restarted: thread 1 received signal: SIGALRM
timer called: timer 0x10073aef0!
Process 80842 stopped and restarted: thread 1 received signal: SIGALRM
timer called: timer 0x10073aef0!
redisplay time taken: 3.162885s

and here's the actual timer callback get called:

(lldb) p t
(atimer *) $0 = 0x000000010073aef0
(lldb) p *t
(atimer) $1 = {
  type = ATIMER_CONTINUOUS
  expiration = {
    tv_sec = 1391689620
    tv_nsec = 380898000
  }
  interval = {
    tv_sec = 2
    tv_nsec = 0
  }
  fn = 0x00000001000b4d90 (Emacs`poll_for_input at keyboard.c:1971)
  client_data = 0x0000000000000000
  next = 0x0000000000000000
}