Re: Emacs 21.2 - Garbage collector frenzy :-)

[Eli Zaretskii]

On 21 Apr 2002, =?iso-8859-1?q?Fran=E7ois?= Pinard wrote:

> This is with Emacs 21.2 that I thought about checking if the problem is
> related to garbage collection, but I remember having observed such CPU
> loops in the latest pretest before 21.2, without much to say about them at
> the time.  Not that I have so much more to say now...  How could I proceed
> towards better reporting the problem?

Try this:

  - Run Emacs under GDB.  Be sure to start GDB from the `src' directory 
    of the Emacs source tree, to make it use the .gdbinit file with all
    the additional commands it defines.

  - When the problem happens, interrupt Emacs with "kill -TSTP PID", 
    where PID is the Emacs process ID, or by typing "C-c" at the window 
    where Emacs is run under GDB.  This should cause GDB to kick in.

  - At the GDB prompt, type "xbacktrace".  It should produce the 
    Lisp-level backtrace showing what function caused the massive GC.

  - Still at the GDB prompt, type "bt" for the C-level backtrace.

  - Repeat the above 3 steps several times, each time continuing Emacs 
    after producing the backtraces.  After that, you should have enough 
    information to figure out what feature(s) causes the massive GC.  
    Post that info here.

The file etc/DEBUG in the Emacs distribution has more hints for debugging 
Emacs.