* bug#35562: "varset" bytecode inline path is never taken
@ 2019-05-04 13:27 Simon Frankau
2019-05-04 16:10 ` Noam Postavsky
2019-05-04 18:16 ` Paul Eggert
0 siblings, 2 replies; 3+ messages in thread
From: Simon Frankau @ 2019-05-04 13:27 UTC (permalink / raw)
To: 35562
[-- Attachment #1: Type: text/plain, Size: 704 bytes --]
While reading the source, I noticed in bytecode.c that:
/* Inline the most common case. */
if (SYMBOLP (sym)
&& !EQ (val, Qunbound)
&& *!XSYMBOL (sym)->u.s.redirect*
&& !SYMBOL_TRAPPED_WRITE_P (sym))
SET_SYMBOL_VAL (XSYMBOL (sym), val);
should be:
/* Inline the most common case. */
if (SYMBOLP (sym)
&& !EQ (val, Qunbound)
&& *XSYMBOL (sym)->u.s.redirect == SYMBOL_PLAINVAL*
&& !SYMBOL_TRAPPED_WRITE_P (sym))
SET_SYMBOL_VAL (XSYMBOL (sym), val);
As it is, the inline case is never run, since "redirect" is always non-zero.
Since I'm new to emacs internals, I don't know how to benchmark to work out
if this makes a noticable performance difference. :)
Thanks,
Simon.
[-- Attachment #2: Type: text/html, Size: 2136 bytes --]
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#35562: "varset" bytecode inline path is never taken
2019-05-04 13:27 bug#35562: "varset" bytecode inline path is never taken Simon Frankau
@ 2019-05-04 16:10 ` Noam Postavsky
2019-05-04 18:16 ` Paul Eggert
1 sibling, 0 replies; 3+ messages in thread
From: Noam Postavsky @ 2019-05-04 16:10 UTC (permalink / raw)
To: Simon Frankau; +Cc: 35562
Simon Frankau <sgf@arbitrary.name> writes:
> While reading the source, I noticed in bytecode.c that:
> && *!XSYMBOL (sym)->u.s.redirect*
> should be:
> && *XSYMBOL (sym)->u.s.redirect == SYMBOL_PLAINVAL*
> As it is, the inline case is never run, since "redirect" is always non-zero.
>
> Since I'm new to emacs internals, I don't know how to benchmark to work out
> if this makes a noticable performance difference. :)
I guess something like this might work (haven't tested to see if
difference is measurable though):
(defvar bug-35562-test-var nil)
(benchmark-run-compiled
(dotimes (_ 1000000)
;; Unroll a bit, so that setting `bug-35562-test-var' takes more
;; time than incrementing loop counter.
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)
(setq bug-35562-test-var nil)))
^ permalink raw reply [flat|nested] 3+ messages in thread
* bug#35562: "varset" bytecode inline path is never taken
2019-05-04 13:27 bug#35562: "varset" bytecode inline path is never taken Simon Frankau
2019-05-04 16:10 ` Noam Postavsky
@ 2019-05-04 18:16 ` Paul Eggert
1 sibling, 0 replies; 3+ messages in thread
From: Paul Eggert @ 2019-05-04 18:16 UTC (permalink / raw)
To: Simon Frankau; +Cc: 35562-done
Thanks for reporting that typo. I verified that the patch improves performance
significantly (50% speedup) on Noam's benchmark, and installed the patch into
the Emacs master branch.
^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2019-05-04 18:16 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2019-05-04 13:27 bug#35562: "varset" bytecode inline path is never taken Simon Frankau
2019-05-04 16:10 ` Noam Postavsky
2019-05-04 18:16 ` Paul Eggert
Code repositories for project(s) associated with this external index
https://git.savannah.gnu.org/cgit/emacs.git
https://git.savannah.gnu.org/cgit/emacs/org-mode.git
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.