Re: [PATCH v5 08/13] ACPI: add perf low power callback

[kernel test robot <lkp@intel.com>]

Hi Stephane,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on next-20220125]
[cannot apply to tip/x86/core rafael-pm/linux-next tip/perf/core v5.17-rc1 v5.16 v5.16-rc8 v5.17-rc1]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Stephane-Eranian/perf-core-add-perf_clear_branch_entry_bitfields-helper/20220127-083516
base:    d25ee88530253138d0b20d43511ca5acbda4e9f7
config: i386-randconfig-a011-20220124 (https://download.01.org/0day-ci/archive/20220127/202201271501.7zuL3YEw-lkp@intel.com/config)
compiler: clang version 14.0.0 (https://github.com/llvm/llvm-project f400a6012c668dfaa73462caf067ceb074e66c47)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/fe7943af61c65b96cff36b8388246531402e7f26
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Stephane-Eranian/perf-core-add-perf_clear_branch_entry_bitfields-helper/20220127-083516
        git checkout fe7943af61c65b96cff36b8388246531402e7f26
        # save the config file to linux build tree
        mkdir build_dir
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross W=1 O=build_dir ARCH=i386 SHELL=/bin/bash drivers/acpi/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/acpi/acpi_pad.c:168:4: error: implicit declaration of function 'perf_lopwr_cb' [-Werror,-Wimplicit-function-declaration]
                           perf_lopwr_cb(true);
                           ^
   1 error generated.


vim +/perf_lopwr_cb +168 drivers/acpi/acpi_pad.c

   135	
   136	static unsigned int idle_pct = 5; /* percentage */
   137	static unsigned int round_robin_time = 1; /* second */
   138	static int power_saving_thread(void *data)
   139	{
   140		int do_sleep;
   141		unsigned int tsk_index = (unsigned long)data;
   142		u64 last_jiffies = 0;
   143	
   144		sched_set_fifo_low(current);
   145	
   146		while (!kthread_should_stop()) {
   147			unsigned long expire_time;
   148	
   149			/* round robin to cpus */
   150			expire_time = last_jiffies + round_robin_time * HZ;
   151			if (time_before(expire_time, jiffies)) {
   152				last_jiffies = jiffies;
   153				round_robin_cpu(tsk_index);
   154			}
   155	
   156			do_sleep = 0;
   157	
   158			expire_time = jiffies + HZ * (100 - idle_pct) / 100;
   159	
   160			while (!need_resched()) {
   161				if (tsc_detected_unstable && !tsc_marked_unstable) {
   162					/* TSC could halt in idle, so notify users */
   163					mark_tsc_unstable("TSC halts in idle");
   164					tsc_marked_unstable = 1;
   165				}
   166				local_irq_disable();
   167	
 > 168				perf_lopwr_cb(true);
   169	
   170				tick_broadcast_enable();
   171				tick_broadcast_enter();
   172				stop_critical_timings();
   173	
   174				mwait_idle_with_hints(power_saving_mwait_eax, 1);
   175	
   176				start_critical_timings();
   177				tick_broadcast_exit();
   178	
   179				perf_lopwr_cb(false);
   180	
   181				local_irq_enable();
   182	
   183				if (time_before(expire_time, jiffies)) {
   184					do_sleep = 1;
   185					break;
   186				}
   187			}
   188	
   189			/*
   190			 * current sched_rt has threshold for rt task running time.
   191			 * When a rt task uses 95% CPU time, the rt thread will be
   192			 * scheduled out for 5% CPU time to not starve other tasks. But
   193			 * the mechanism only works when all CPUs have RT task running,
   194			 * as if one CPU hasn't RT task, RT task from other CPUs will
   195			 * borrow CPU time from this CPU and cause RT task use > 95%
   196			 * CPU time. To make 'avoid starvation' work, takes a nap here.
   197			 */
   198			if (unlikely(do_sleep))
   199				schedule_timeout_killable(HZ * idle_pct / 100);
   200	
   201			/* If an external event has set the need_resched flag, then
   202			 * we need to deal with it, or this loop will continue to
   203			 * spin without calling __mwait().
   204			 */
   205			if (unlikely(need_resched()))
   206				schedule();
   207		}
   208	
   209		exit_round_robin(tsk_index);
   210		return 0;
   211	}
   212	

---
0-DAY CI Kernel Test Service, Intel Corporation
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