From: Willy Tarreau <w@1wt.eu>
Date: Thu, 28 May 2026 14:48:51 +0000 (+0200)
Subject: BUG/MEDIUM: threads: ignore max-threads-per-group when thread-groups is set
X-Git-Tag: v3.4.0~56
X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=f5847d11f796edaec3d501ac58eafcbd32efa6bf;p=thirdparty%2Fhaproxy.git

BUG/MEDIUM: threads: ignore max-threads-per-group when thread-groups is set

As documented, max-threads-per-group is the default number of threads
to arrange in a group before creating another group, and is only meant
to be used when thread-groups is not set.

However it was always enforced, so configs like:

   global
       thready-groups 2

which were sufficient in 3.2 and above to start with 64-128 threads
are now suddenly limited to 32 threads! Let's relax the limit when
thread-groups is set!

No backport is needed since this is only 3.4.
---

diff --git a/src/thread.c b/src/thread.c
index a3e362d52..bb733a602 100644
--- a/src/thread.c
+++ b/src/thread.c
@@ -1679,8 +1679,11 @@ void thread_detect_count(void)
 	if (global.nbthread)
 		thr_min = thr_max = global.nbthread;
 
-	if (global.nbtgroups)
+	if (global.nbtgroups) {
 		grp_min = grp_max = global.nbtgroups;
+		/* ignore max-threads-per-group if thread-groups is configured */
+		global.maxthrpertgroup = MAX_THREADS_PER_GROUP;
+	}
 
 #if defined(USE_THREAD)
 	/* Adjust to boot settings if not forced */