patch for X wakeups

[Carlos R. Mafra]

Hi,


> I'm sure many here on the list have seen the
> X: do_setitimer (it_real_fn)
> wakeups and wondered if it was possible to get rid of these....

Yes! On my idle desktop this do_setitimer is the biggest offender:

[root at localhost mafra]# powertop -d
PowerTOP 1.9    (C) 2007 Intel Corporation 

Collecting data for 15 seconds 
Cn                Avg residency
C0 (cpu running)        ( 0,1%)
C1                0,0ms ( 0,0%)
C2                0,0ms ( 0,0%)
C3                0,0ms ( 0,0%)
C4              282,3ms (99,9%)
P-states (frequencies)
  2,00 Ghz     0,0%
  1,80 Ghz     0,0%
  1,60 Ghz     0,0%
   600 Mhz   100,0%
Wakeups-from-idle per second :  3,5     interval: 15,0s
Top causes for wakeups:
  35,4% (  1,1)                 X : do_setitimer (it_real_fn) 
  33,3% (  1,1)                 X : schedule_timeout (process_timeout) 
  14,6% (  0,5)     <kernel core> : queue_delayed_work_on (delayed_work_timer_fn) 
   6,2% (  0,2)              init : schedule_timeout (process_timeout) 
   4,2% (  0,1)     <kernel core> : neigh_table_init_no_netlink (neigh_periodic_timer) 
   2,1% (  0,1)       <interrupt> : PS/2 keyboard/mouse/touchpad 
   2,1% (  0,1)     <kernel core> : page_writeback_init (wb_timer_fn) 
   2,1% (  0,1)     <kernel core> : inet_initpeers (peer_check_expire)


> ... wonder no more; I've made a patch to X that optimizes the X server 
> and gets rid of these wakeups for pretty much all cases. I've attached 
> the patch to this email for those brave enough to build their own X 
> server. Note: building X is not easy; I strongly recommend using the 
> packaging system of your distro and just adding the patch to that, and 
> then build a new package. Building X can be a great way to hose a system 
> if you're not very careful

I hope Mandriva 2008.0 will put this patch in the update list!

Thanks,
Carlos