Hi @all, I freshly installed linux on my SUN Ultra 60 /w 2x 450MHz CPUs. First I tested kernel 5.8.x and couldn't get SMP to work on both CPUs - just the first CPU will be activated. Same results with kernel 4.19.146 . Kernel 3.18.140 runs perfectly on both CPUs. Might be the problem that the CPUs numbering scheme is not linear: CPU1 is #0 and CPU2 is #2 (NOT #1) Below you find some infos. With kernel 5.8.14 (also tested 5.4.66 and 4.19.146) : dmesg (cutted) [ 0.000335] Linux version 5.8.14-gentoo (root@compilenode1) (sparc64-unknown-linux-gnu-gcc (Gentoo Hardened 9.3.0-r1 p3) 9.3.0, GNU ld (Gentoo 2.34 p6) 2.34.0) #2 SMP Thu Oct 8 10:40:33 CEST 2020 ... [ 0.918138] percpu: Embedded 10 pages/cpu s42648 r8192 d31080 u2097152 [ 0.942080] pcpu-alloc: s42648 r8192 d31080 u2097152 alloc=1*4194304 [ 0.942090] pcpu-alloc: [0] 0 1 ... [ 1.252126] rcu: Hierarchical RCU implementation. [ 1.268124] rcu: RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=2. [ 1.288896] rcu: RCU calculated value of scheduler-enlistment delay is 100 jiffies. [ 1.312586] rcu: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=2 [ 1.334035] NR_IRQS: 2048, nr_irqs: 2048, preallocated irqs: 1 ... [ 1.532316] Calibrating delay using timer specific routine.. 905.89 BogoMIPS (lpj=452945) ... [ 1.539394] rcu: Hierarchical SRCU implementation. [ 1.540102] smp: Bringing up secondary CPUs ... [ 1.540120] smp: Brought up 1 node, 1 CPU ######## ultra60-1 ~ # lscpu Architecture: sparc64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Big Endian CPU(s): 1 On-line CPU(s) list: 0 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 1 NUMA node(s): 1 Model name: TI UltraSparc II (BlackBird) NUMA node0 CPU(s): 0 Flags: sun4u ######## ultra60-1 ~ # cat /proc/cpuinfo cpu : TI UltraSparc II (BlackBird) fpu : UltraSparc II integrated FPU pmu : ultra12 prom : OBP 3.31.0 2001/07/25 20:31 type : sun4u ncpus probed : 2 ncpus active : 1 D$ parity tl1 : 0 I$ parity tl1 : 0 cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis Cpu0ClkTck : 000000001ad38c39 MMU Type : Spitfire MMU PGSZs : 8K,64K,512K,4MB State: CPU0: online ######## ultra60-1 ~ # cat /sys/devices/system/cpu/offline 1 ultra60-1 ~ # cat /sys/devices/system/cpu/online 0 ################################################################# With kernel 3.18.140 dmesg (cutted) [ 0.000000] PROMLIB: Sun IEEE Boot Prom 'OBP 3.31.0 2001/07/25 20:31' ... [ 0.000000] Linux version 3.18.140 (root@compilenode1) (gcc version 9.3.0 (Gentoo Hardened 9.3.0-r1 p3) ) #7 SMP Thu Oct 8 15:37:47 CEST 2020 ... [ 0.000000] PERCPU: Embedded 8 pages/cpu @fffff800bf800000 s21760 r8192 d35584 u2097152 [ 0.000000] pcpu-alloc: s21760 r8192 d35584 u2097152 alloc=1*4194304 [ 0.000000] pcpu-alloc: [0] 0 2 ... [ 0.000000] Hierarchical RCU implementation. [ 0.000000] RCU restricting CPUs from NR_CPUS=4 to nr_cpu_ids=3. [ 0.000000] RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=3 [ 0.000000] NR_IRQS:2048 nr_irqs:2048 1 ... [ 82.644201] CPU 2: synchronized TICK with master CPU (last diff 0 cycles, maxerr 535 cycles) [ 82.644302] Brought up 2 CPUs ######## ultra60-1 ~ # lscpu Architecture: sparc64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Big Endian CPU(s): 2 On-line CPU(s) list: 0,2 Thread(s) per core: 1 Core(s) per socket: 1 Socket(s): 2 NUMA node(s): 1 Model name: TI UltraSparc II (BlackBird) NUMA node0 CPU(s): 0-3 Flags: sun4u ######## ultra60-1 ~ # cat /proc/cpuinfo cpu : TI UltraSparc II (BlackBird) fpu : UltraSparc II integrated FPU pmu : ultra12 prom : OBP 3.31.0 2001/07/25 20:31 type : sun4u ncpus probed : 2 ncpus active : 2 D$ parity tl1 : 0 I$ parity tl1 : 0 cpucaps : flush,stbar,swap,muldiv,v9,mul32,div32,v8plus,vis Cpu0ClkTck : 000000001ad37db2 Cpu2ClkTck : 000000001ad37db2 MMU Type : Spitfire MMU PGSZs : 8K,64K,512K,4MB State: CPU0: online CPU2: online ######## ultra60-1 ~ # cat /sys/devices/system/cpu/offline ultra60-1 ~ # cat /sys/devices/system/cpu/online 0,2 best regards, Rüdiger
