[PATCH] Fix futures, %worker-count shouldn't be zero to prevent halting

Nala Ginrut <[email protected]> Thu, 14 Aug 2025 22:04:49 +0900

Newsgroups	gmane.lisp.guile.devel
Message-ID	<CAPjoZoc=XQ3OQ722FWYU+t6Kexc9yjExN2ox_zgfjH59fk9UwA@mail.gmail.com>

Hi folks!
When I was trying to fix a halting bug in GNU Artanis' new runner module
based on futures for async requests. I found it doesn't work for my cloud
server which has only one CPU.
The reason is because the%worker-count will be zero when there's only one
cpu. So it will do nothing for the existing futures in the queue. The
proper fix should be always keep %worker-count when there's just one cpu.

It was tested successfully on my server machine.
Attached the patch.

Thanks!

0001-Fix-futures-worker-count-shouldn-t-be-zero-to-preven.patch (text/x-patch, 790 B)

From e675b77a1c7de7ca03566a1f71ac75ea3ed24cb1 Mon Sep 17 00:00:00 2001
From: Nala Ginrut <[email protected]>
Date: Thu, 14 Aug 2025 21:37:42 +0900
Subject: [PATCH] Fix futures, %worker-count shouldn't be zero to prevent
 halting

---
 module/ice-9/futures.scm | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/module/ice-9/futures.scm b/module/ice-9/futures.scm
index 4a462839a..a830858b0 100644
--- a/module/ice-9/futures.scm
+++ b/module/ice-9/futures.scm
@@ -264,7 +264,9 @@ adding it to the waiter queue."
 
 (define %worker-count
   (if (provided? 'threads)
-      (- (current-processor-count) 1)
+      (if (= 1 (current-processor-count))
+          1
+          (- (current-processor-count) 1))
       0))
 
 ;; A dock of workers that stay here forever.
-- 
2.43.0