Re: Memory usage report

[Ihor Radchenko]

> I guess I don't understand the utility of knowing, e.g., which Lisp
> string in the current session is the longest one.  What would you do
> with such information?

Knowing a buffer with largest total memory occupied by buffer-local
variables might be useful.


Eli Zaretskii <eliz@gnu.org> writes:

>> From: Lars Ingebrigtsen <larsi@gnus.org>
>> Cc: emacs-devel@gnu.org
>> Date: Fri, 18 Sep 2020 14:59:24 +0200
>> 
>> Eli Zaretskii <eliz@gnu.org> writes:
>> 
>> >> That can have significant memory?
>> >
>> > Some of them could, yes.
>> 
>> Do you know which ones?
>
> bidi_cache, for one.
>
>> > Why would an image cache take that much? we flush it from time to
>> > time, and I have difficulty believing that all those users reporting
>> > large memory footprints load thousands of images every hour of every
>> > day.
>> 
>> It is unlikely that "all those users" use that many images, but some
>> may.  (As you no doubt remember, calling `image-size' in a loop will
>> kill Emacs with an out of memory fault.)
>
> That loop is highly unlikely to happen in practice, certainly not
> happen constantly in a long-lived session.
>
>> >> > Which variables did you have in mind in this context?  Can you show an
>> >> > example?
>> >> 
>> >> It'd just traverse all the variables and compute the "largest" ones.
>> >
>> > Again, they are included in the GC report.  So what do you expect to
>> > see?
>> 
>> I expect to see what variables take "all that size"?  I'm not sure what
>> you're asking here.
>
> I guess I don't understand the utility of knowing, e.g., which Lisp
> string in the current session is the longest one.  What would you do
> with such information?
>
>> > So, while a more detailed report might be nice to have, I don't see
>> > how it would help to diagnose "leaks" of the kind we are discussing
>> > now on the bug list.
>> 
>> I am not talking about any bug report in particular.  If I were, that is
>> where I would have posted this.
>
> Then I guess I don't understand the purpose of the features you'd like
> to have.  Can you explain?