Re: silent PC vs. emacs

[Dan Nicolaescu]

Eli Zaretskii <address@hidden> writes:

  > > Date: Sat, 2 Sep 2006 09:11:42 -0700
  > > From: Dan Nicolaescu <address@hidden>
  > > Cc: address@hidden, address@hidden, address@hidden
  > > 
  > > On my Fedora Core 5 machine, emacs compiled with the Lucid toolkit
  > > doing:
  > > 
  > > emacs -D -Q&
  > > strace -p PID_OF_EMACS
  > > 
  > > Prints things like this a few times a second:
  > > 
  > > gettimeofday({1157213370, 605043}, NULL) = 0
  > > select(5, [4], NULL, NULL, {25, 670718}) = ? ERESTARTNOHAND (To be 
restarted)
  > > --- SIGALRM (Alarm clock) @ 0 (0) ---
  > > gettimeofday({1157213370, 708405}, NULL) = 0
  > > gettimeofday({1157213370, 708534}, NULL) = 0
  > > gettimeofday({1157213370, 708662}, NULL) = 0
  > > setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 99743}}, NULL) = 0
  > > sigreturn()                             = ? (mask now [])
  > > gettimeofday({1157213370, 709043}, NULL) = 0
  > > select(5, [4], NULL, NULL, {25, 566718}) = ? ERESTARTNOHAND (To be 
restarted)
  > > --- SIGALRM (Alarm clock) @ 0 (0) ---
  > > gettimeofday({1157213370, 812405}, NULL) = 0
  > > gettimeofday({1157213370, 812535}, NULL) = 0
  > > gettimeofday({1157213370, 812663}, NULL) = 0
  > > setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={0, 99742}}, NULL) = 0
  > > sigreturn()                             = ? (mask now [])
  > > ....
  > > 
  > > so there is some activity all the time. Is this something that can be
  > > avoided?
  > 
  > I can think of several explanations:
  > 
  >  . The blink-cursor mode uses a timer (that probably explains setitmer
  >    and SIGALRM)
  > 
  >  . select calls are issued when Emacs enters the idle loop
  > 
  >  . The rest might be because the blink-cursor mode causes signals,
  >    which then require various system calls, like select, to be
  >    restarted


The same thing happens when blink-cursor-mode is turned off. It is a
bit less frequent, but still a few times a second.