On 10/1/23 04:39, Eli Zaretskii wrote: >> Date: Sat, 30 Sep 2023 20:57:31 -0400 >> From: Chris Hanson >> >> When using "xscheme.el" to start and interact with MIT/GNU Scheme in a >> subprocess, the performance significantly degraded in Emacs 29.1. It >> worked well in older releases. >> >> Here is a recipe: >> >> emacs -Q >> M-x load-library RET xscheme RET >> M-x run-scheme RET >> >> and see how slowly the process output is printed as Scheme starts. >> Compare this to Emacs 28.2 or earlier. > > Please post the comparison as you see it on your system, preferably in > quantitative terms (e.g., time it takes to read and process some chunk > of text in both versions), and using the same version of MIT/GNU > Scheme. > > FWIW, I see no changes in xscheme.el between v28.1 and v29.1, except > some minor aesthetic changes and renames of functions. So I wonder > how come you see a significant slowdown. Attached find two screen grabs showing 28.2 and 29.1; you'll see the difference is dramatic. In both cases the same MIT/GNU Scheme version was used. (FYI: I'm the MIT/GNU Scheme maintainer, as well as the original author of "xscheme.el".) I saw that there were no relevant differences in "xscheme.el" but I never thought that was relevant. I believe this has something to do with how piped subprocesses are being managed. I've not looked deeply into the C code for this, but I could find no mention of anything to do with pipes in NEWS. I don't think there's anything funny going on with how MIT/GNU Scheme manages stdout but I'll look into it.