Re: Emacs in CVS plus GTK patches hogs CPU

[Simon Josefsson <jas@extundo.com>]

"Jan D." <jan.h.d@swipnet.se> writes:

>> 
>> "Jan D." <jan.h.d@swipnet.se> writes:
>> 
>> > Can you strace or truss the Emacs process to see if is in some sort of busy
>> > wait?  A very short timeout perhaps?
>> 
>> Yes, it is a busy wait:
>> 
>> ...
>> kill(17005, SIGIO)                      = 0
>> gettimeofday({1042058269, 284790}, NULL) = 0
>> select(8, [3 7], NULL, NULL, {0, 451252}) = 1 (in [7], left {0, 453096})
>> gettimeofday({1042058269, 284976}, NULL) = 0
>> getpid()                                = 17005
>> kill(17005, SIGIO)                      = 0
>> gettimeofday({1042058269, 285079}, NULL) = 0
>> select(8, [3 7], NULL, NULL, {0, 450963}) = 1 (in [7], left {0, 451143})
>> gettimeofday({1042058269, 285265}, NULL) = 0
>> getpid()                                = 17005
>> kill(17005, SIGIO)                      = 0
>> gettimeofday({1042058269, 285368}, NULL) = 0
>> select(8, [3 7], NULL, NULL, {0, 450674}) = 1 (in [7], left {0, 451143})
>> gettimeofday({1042058269, 285554}, NULL) = 0
>> 
>> This doesn't look GTK related, but rather network process related,
>> though.  Hm.  17005 is the pid of the emacs process itself.  Does GTK
>> catch SIGIO or something?
>
> I could not find anything in the GTK source.  This looks like fd 7 is ready
> for reading everytime select is called and then select returns immediately.
> The X connection is usually a very low fd, 3 or 4 so I guess 3 is the
> X connection and 7 is some network connection that for example Gnus
> has open.

Yup.

> Could it be that Gnus/Emacs doesn't read from it or perhaps it is
> closed at the other side, but Gnus/Emacs does not close this side?
> As seen above, there is no read between the selects even though 7
> clearly is readable.

The process isn't running elisp any more, so Gnus has no chance to
read from the process.  It is simply inflooping around trying to read
from a (by now likely) dead process.

> You could try to start emacs, and strace it to see if this other fd 7
> is opened with Gnus or something else.

lsof on the emacs process says it is a socket, and it is the last
socket allocated so it most likely Gnus related.

OK, I'm killing the debugger (I did cvs up so source tracing in the
debugger is lost anyway) and forgetting the problem until I see it
again.