On Wed, Jan 14, 2026 at 03:47:15PM +0100, Stefan Fritsch wrote:

[...]

> > > Updated diff below that should fix all architectures. sparc64 already has 
> > > the correct ordering. Boot tested on amd64, i386, arm64.
> > 
> > On arm64, the slow cores are typically (but not always) listed before
> > the fast cores.  Don't think that is a good reason not to change the
> > order of the list to be more sensible.
> 
> Does this mean that the boot cpu is then a slow core, too?
> 
> In the long term, one probably wants to have some field in cpu_info that
> denotes the core type and then make intrmap_create() use that info to
> prefer the fastest cores.
> 
> As noted by tb@, the previous diff broke !MULTIPROCESSOR configurations.
> New diff attached.

Not my area. Should this be committed?

diff --git a/sys/arch/alpha/alpha/cpu.c b/sys/arch/alpha/alpha/cpu.c
index 23b25c94219..38425f1d905 100644
--- a/sys/arch/alpha/alpha/cpu.c
+++ b/sys/arch/alpha/alpha/cpu.c
@@ -419,7 +419,7 @@ cpu_announce_extensions(struct cpu_info *ci)
 void
 cpu_boot_secondary_processors(void)
 {
-	struct cpu_info *ci;
+	struct cpu_info *ci, *ci_last;
 	u_long i;
 
 	for (i = 0; i < ALPHA_MAXPROCS; i++) {
@@ -434,8 +434,10 @@ cpu_boot_secondary_processors(void)
 		/*
 		 * Link the processor into the list, and launch it.
 		 */
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		atomic_setbits_ulong(&ci->ci_flags, CPUF_RUNNING);
 		atomic_setbits_ulong(&cpus_running, (1UL << i));
 		ncpus++;
diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c
index 18cfb8d6377..4d56f320c33 100644
--- a/sys/arch/amd64/amd64/cpu.c
+++ b/sys/arch/amd64/amd64/cpu.c
@@ -729,8 +729,11 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 		sched_init_cpu(ci);
 		ncpus++;
 		if (ci->ci_flags & CPUF_PRESENT) {
-			ci->ci_next = cpu_info_list->ci_next;
-			cpu_info_list->ci_next = ci;
+			struct cpu_info *ci_last = cpu_info_list;
+
+			while (ci_last->ci_next != NULL)
+				ci_last = ci_last->ci_next;
+			ci_last->ci_next = ci;
 		}
 #else
 		printf("%s: not started\n", sc->sc_dev.dv_xname);
diff --git a/sys/arch/arm/arm/cpu.c b/sys/arch/arm/arm/cpu.c
index f51404f73be..005211ba35f 100644
--- a/sys/arch/arm/arm/cpu.c
+++ b/sys/arch/arm/arm/cpu.c
@@ -354,10 +354,14 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
 		ci = &cpu_info_primary;
 		ci->ci_flags |= CPUF_RUNNING | CPUF_PRESENT | CPUF_PRIMARY;
 	} else {
+		struct cpu_info *ci_last;
+
 		ci = malloc(sizeof(*ci), M_DEVBUF, M_WAITOK | M_ZERO);
 		cpu_info[dev->dv_unit] = ci;
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		ci->ci_flags |= CPUF_AP;
 		ncpus++;
 	}
diff --git a/sys/arch/arm64/arm64/cpu.c b/sys/arch/arm64/arm64/cpu.c
index f9784e432db..8f59fc03e0f 100644
--- a/sys/arch/arm64/arm64/cpu.c
+++ b/sys/arch/arm64/arm64/cpu.c
@@ -1481,6 +1481,7 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
 	struct cpu_info *ci;
 	void *kstack;
 #ifdef MULTIPROCESSOR
+	struct cpu_info *ci_last;
 	uint64_t mpidr = READ_SPECIALREG(mpidr_el1);
 #endif
 	uint32_t opp;
@@ -1494,8 +1495,10 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
 	} else {
 		ci = malloc(sizeof(*ci), M_DEVBUF, M_WAITOK | M_ZERO);
 		cpu_info[dev->dv_unit] = ci;
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		ci->ci_flags |= CPUF_AP;
 		ncpus++;
 	}
diff --git a/sys/arch/i386/i386/cpu.c b/sys/arch/i386/i386/cpu.c
index c5f18dd4433..e3b4d7cc589 100644
--- a/sys/arch/i386/i386/cpu.c
+++ b/sys/arch/i386/i386/cpu.c
@@ -234,6 +234,7 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 	struct cpu_info *ci;
 
 #ifdef MULTIPROCESSOR
+	struct cpu_info *ci_last;
 	int cpunum = sc->sc_dev.dv_unit;
 	vaddr_t kstack;
 	struct pcb *pcb;
@@ -365,8 +366,10 @@ cpu_attach(struct device *parent, struct device *self, void *aux)
 		identifycpu(ci);
 		clockqueue_init(&ci->ci_queue);
 		sched_init_cpu(ci);
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		ncpus++;
 #endif
 		break;
diff --git a/sys/arch/mips64/mips64/cpu.c b/sys/arch/mips64/mips64/cpu.c
index 040669d397b..fe45ce0970c 100644
--- a/sys/arch/mips64/mips64/cpu.c
+++ b/sys/arch/mips64/mips64/cpu.c
@@ -95,9 +95,13 @@ cpuattach(struct device *parent, struct device *dev, void *aux)
 				panic("unable to allocate cpu_info");
 		}
 	} else {
+		struct cpu_info *ci_last;
+
 		ci = &cpu_info_secondaries[cpuno - 1];
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		ci->ci_flags |= CPUF_PRESENT;
 	}
 #else
diff --git a/sys/arch/riscv64/riscv64/cpu.c b/sys/arch/riscv64/riscv64/cpu.c
index e8400d4eed3..1c2c2a1341c 100644
--- a/sys/arch/riscv64/riscv64/cpu.c
+++ b/sys/arch/riscv64/riscv64/cpu.c
@@ -195,10 +195,14 @@ cpu_attach(struct device *parent, struct device *dev, void *aux)
 		ci->ci_flags |= CPUF_RUNNING | CPUF_PRESENT | CPUF_PRIMARY;
 		csr_set(sie, SIE_SSIE);
 	} else {
+		struct cpu_info *ci_last;
+
 		ci = malloc(sizeof(*ci), M_DEVBUF, M_WAITOK | M_ZERO);
 		cpu_info[dev->dv_unit] = ci;
-		ci->ci_next = cpu_info_list->ci_next;
-		cpu_info_list->ci_next = ci;
+		ci_last = cpu_info_list;
+		while (ci_last->ci_next != NULL)
+			ci_last = ci_last->ci_next;
+		ci_last->ci_next = ci;
 		ci->ci_flags |= CPUF_AP;
 		ncpus++;
 	}