Ideas for debugging excessive garbage collection bugs?

Ideas for debugging excessive garbage collection bugs?

[William K. Foster]

Hello,

I am wondering if anybody has any strategies they are willing to share
to track down why excessive garbage collection is happening in my Emacs
v20.7.1 with some personal additions when I do find-file?

The excessive garbage collection appears to be a performance bottleneck.

Thanks.

-William

Re: Ideas for debugging excessive garbage collection bugs?

[Stefan Monnier]

> I am wondering if anybody has any strategies they are willing to share
> to track down why excessive garbage collection is happening in my Emacs
> v20.7.1 with some personal additions when I do find-file?

I don't have any good advice, but I will point out that the problem is not
excessive GC, but excessive allocation.


	Stefan

Re: Ideas for debugging excessive garbage collection bugs?

[William K. Foster]

Stefan,

Sorry for not being clearer. 

  How do I debug the source of allocations in Emacs?

  Is there a good break point to set that would be
  on the stack for any allocation, I could then look
  at several stack traces to see statistically where
  the culprit is probably coming form.

Thanks.

-William


At 11:19 AM 11/8/2002, Stefan Monnier wrote:
>> I am wondering if anybody has any strategies they are willing to share
>> to track down why excessive garbage collection is happening in my Emacs
>> v20.7.1 with some personal additions when I do find-file?
>
>I don't have any good advice, but I will point out that the problem is not
>excessive GC, but excessive allocation.
>
>
>        Stefan

Re: Ideas for debugging excessive garbage collection bugs?

[Eli Zaretskii]

> From: "William K. Foster" <William.Foster@synopsys.com>
> Date: Fri, 08 Nov 2002 11:36:30 -0800
> 
>   How do I debug the source of allocations in Emacs?

You could invoke (print (garbage-collect)) frequently and find the
part of its report that grows the most.  That would tell you what
objects are being consed very frequently.  Then you could put a
breakpoint at the C function which allocates that type of Lisp
objects, and see what the backtrace shows when the breakpoint is hit.

Re: Ideas for debugging excessive garbage collection bugs?

[Richard Stallman]

Something in your code must be consing a lot of data structure.
So the issue is to find out what.

First you could try just increasing gc-cons-threshold and see if that
gives acceptable results.