Re: slow saving of scores when leaving a virtual (nnml+) group

[Eric Abrahamsen <eric@ericabrahamsen.net>]

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Eric S Fraga <e.fraga@ucl.ac.uk> writes:

> Hello all,
>
> recently (past week or two), I've noticed a slow down in leaving some of
> my nnml groups.  Using the profiler, I see the outcomes shown below,
> capturing cpu and memory when entering a virtual group, that collects 3
> different nnml groups, and then immediately leaving that group.  A
> significant amount of time is taken saving scores, as far as I can tell.
> I use adaptive scoring.  Nothing with respect to scoring has changed in
> my configuration in some time (years probably).
>
> The offending function appears to be "lisp--local-defform-body-p" with
> large memory and cpu use.
>
> Cpu report (partly expanded):
>
>        10133  79% - command-execute
>         8519  66%  - funcall-interactively
>         4767  37%   - gnus-summary-exit
>         4659  36%    - gnus-score-save
>         4655  36%     - gnus-pp
>         4655  36%      - pp
>         4655  36%       - pp-to-string
>         4655  36%        - pp-fill
>         4647  36%         - pp--object
>         4627  36%          - pp-fill
>         4615  36%           - pp-fill
>         4555  35%            - pp-fill
>         4263  33%             - pp-fill
>         4243  33%              - indent-according-to-mode
>         4243  33%               - lisp-indent-line
>         4163  32%                - calculate-lisp-indent
>         4163  32%                 - lisp-indent-function
>         4163  32%                    lisp--local-defform-body-p
>           48   0%                + lisp-ppss

A few weeks ago Stefan Monnier made a change to lisp-ppss. It was meant
to improve performance, but the timing looks very suspicious and it may
have had unexpected side effects. The commit is f411cc3a9578eae4ea4549,
I've attached a patch that reverts it, you might give this a try? If it
clearly fixes the problem, I would open a bug report and cc Stefan.


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diff --git a/lisp/emacs-lisp/lisp-mode.el b/lisp/emacs-lisp/lisp-mode.el
index 1990630608d..3613c8d88ec 100644
--- a/lisp/emacs-lisp/lisp-mode.el
+++ b/lisp/emacs-lisp/lisp-mode.el
@@ -876,7 +876,7 @@ lisp-ppss
 2 (counting from 0).  This is important for Lisp indentation."
   (unless pos (setq pos (point)))
   (let ((pss (syntax-ppss pos)))
-    (if (and (not (nth 2 pss)) (nth 9 pss))
+    (if (nth 9 pss)
         (let ((sexp-start (car (last (nth 9 pss)))))
           (parse-partial-sexp sexp-start pos nil nil (syntax-ppss sexp-start)))
       pss)))