pfSense » pfSense Plus

I’ve started to observe a CPU hog of one CPU core on APU2 box running pfSense 23.05.

dtrace showed:

                       kernel`pmap_copy              33
                   kernel`amd64_syscall              33
                 kernel`vm_radix_insert              35
               kernel`vm_map_pmap_enter              37
        kernel`vm_radix_lookup_unlocked              38
                      kernel`memcpy_std              38
            kernel`vm_object_deallocate              39
         kernel`pmap_enter_quick_locked              41
        kernel`em_update_stats_counters              43
              kernel`copyout_nosmap_std              43
          kernel`ck_epoch_poll_deferred              44
                  kernel`sbuf_put_bytes              46
          kernel`vm_page_pqbatch_submit              48
                 kernel`pmap_remove_pte              51
                 kernel`pmap_pvh_remove              53
         kernel`vm_pqbatch_process_page              54
              kernel`cpu_search_highest              56
                    kernel`get_pv_entry              57
        kernel`pmap_try_insert_pv_entry              59
             kernel`vm_map_lookup_entry              65
                 kernel`epoch_call_task              92
                      kernel`pmap_enter             101
                        kernel`vm_fault             110
                        kernel`pagecopy             110
                    kernel`0xffffffff81             133
                      kernel`lock_delay             145
               kernel`pmap_remove_pages             203
                    kernel`_thread_lock             415
                    kernel`pagezero_std             490
                       kernel`assert_rw             532
                     kernel`acpi_cpu_c1             600
                    kernel`callout_lock             641
                      kernel`kern_yield            1206
              kernel`_callout_stop_safe            2010
                  kernel`spinlock_enter            2032
                  kernel`tcp_timer_stop            2703
                                    0x0            5927
                   kernel`spinlock_exit           40964
                        kernel`cpu_idle           61943
                    kernel`sched_idletd           76722

The symptom is that the kernel thread "kernel{if_io_tqg_1}” consumes 100% of the CPU core.