Subject: bug#66288: 29.1; Performance regression using pipe for subprocess

From: Chris Hanson <[email-masked]>
Date: Mon, 2 Oct 2023 19:23:25 -0400

I've been running the tests with a pre-release version of MIT/GNU 
Scheme. But I re-ran them with 11.2 and it had the same behavior as the 
pre-release.

I'm running Ubuntu 22.04 LTS, and I built 28.2 and 29.1 from source (I 
don't usually use the Emacs that comes with the distro). I've also seen 
the slowdown on my laptop with Debian 12, though I haven't done as much 
testing there.

I have an old laptop running macOS; I can try that too.

One other thing comes to mind: is it possible that this is a problem 
with native compilation? I built both 28.2 and 29.1 to use native 
compilation. Did anything relevant change in 29.1?

On 10/2/23 15:27, Dmitry Gutov wrote:
> On 02/10/2023 22:12, Gerd Möllmann wrote:
>> Chris Hanson<[email-masked]>  writes:
>>
>> FWIW, I can't reproduce the slowdown on macOS.  I get the
>>
>>> ;process time: 0 (0 RUN + 0 GC); real time: 1
>> on the emacs-29 branch with emacs-29.1 and HEAD (same on master).
> 
> Curious: I reproduced it once (master, an older session), but then not 
> anymore, all subsequent attempts look fine/instant.
> 
> That's with MIT Scheme 11.2, though (the output is a little different, 
> chiefly the list of bindings at the top).