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X-CSE-ConnectionGUID: QtXWik5VQmiAcO2+NCz/0g== X-CSE-MsgGUID: DKplN1IgTim/dkNPFnmiNg== X-IronPort-AV: E=McAfee;i="6800,10657,11483"; a="53117921" X-IronPort-AV: E=Sophos;i="6.16,284,1744095600"; d="scan'208";a="53117921" Received: from fmviesa005.fm.intel.com ([10.60.135.145]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Jul 2025 09:02:45 -0700 X-CSE-ConnectionGUID: itwYFqXiTEqwrPVag3Qfzw== X-CSE-MsgGUID: Bg1RtVG/RPuhzHyjrcaYag== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,284,1744095600"; d="scan'208";a="158679754" Received: from lkp-server01.sh.intel.com (HELO 0b2900756c14) ([10.239.97.150]) by fmviesa005.fm.intel.com with ESMTP; 03 Jul 2025 09:02:42 -0700 Received: from kbuild by 0b2900756c14 with local (Exim 4.96) (envelope-from ) id 1uXMOW-0002ky-0f; Thu, 03 Jul 2025 16:02:40 +0000 Date: Fri, 4 Jul 2025 00:02:23 +0800 From: kernel test robot To: Christoph Lameter via B4 Relay , Anna-Maria Behnsen , Frederic Weisbecker , Ingo Molnar , Thomas Gleixner Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, linux-mm@kvack.org, sh@gentwo.org, Darren Hart , "Christoph Lameter (Ampere)" Subject: Re: [PATCH] Skew tick for systems with a large number of processors Message-ID: <202507032322.5jzirIYw-lkp@intel.com> References: <20250702-tick_skew-v1-1-ff8d73035b02@gentwo.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250702-tick_skew-v1-1-ff8d73035b02@gentwo.org> X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 997FA180028 X-Stat-Signature: ttuqr6o94x4b6uw1ho44w3w6jpq5385u X-Rspam-User: X-HE-Tag: 1751558566-321180 X-HE-Meta: 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 StUafEao sszmih0vDUzxNZCiU6Txkx+9/2s4/DRi/pZ+9ns3TSnyPS18aX/GEfrdMn7fZ2/eHtUZTioDSg3EAy0/TdxP9Nq6sqenFSXDkMk1Soa7+q49F9LZjT/VOS6Fr1QiYHDFXzn9ZiszNl1aSDz2KNeYlQ1od2lSd7ApP/o6uHxZ/3HExbv3rnpEvx22K99HygMvGUqJSMPWeaGvIoInBsglHTHlgNqFYgC/uPm1T2rWCESN5RIK5sCogfXCwXnbkk2W/lVUaphDbdTSlAo1IgU3BQ3upnRXKOkF80n/ikteqA/5y44Lpd4umZgVKuBlSbhIiD13Xi9vTxNVj+90BnHFGr8+SwkiRLFY3o0feUlbrTa84fM5vWgF9h5KnVILLYlAdQLSopSrVGpSx5yDrUcU/fRkXtC3wQgi3y9z1xI5zW9YOW/od/fM+2yh6vbUG4MvUEOG7r+Ran0ncu8AS2zBIw2j643WRQURAY+iJ X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Christoph, kernel test robot noticed the following build errors: [auto build test ERROR on 66701750d5565c574af42bef0b789ce0203e3071] url: https://github.com/intel-lab-lkp/linux/commits/Christoph-Lameter-via-B4-Relay/Skew-tick-for-systems-with-a-large-number-of-processors/20250703-034357 base: 66701750d5565c574af42bef0b789ce0203e3071 patch link: https://lore.kernel.org/r/20250702-tick_skew-v1-1-ff8d73035b02%40gentwo.org patch subject: [PATCH] Skew tick for systems with a large number of processors config: arc-randconfig-002-20250703 (https://download.01.org/0day-ci/archive/20250703/202507032322.5jzirIYw-lkp@intel.com/config) compiler: arc-linux-gcc (GCC) 12.4.0 reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20250703/202507032322.5jzirIYw-lkp@intel.com/reproduce) If you fix the issue in a separate patch/commit (i.e. not just a new version of the same patch/commit), kindly add following tags | Reported-by: kernel test robot | Closes: https://lore.kernel.org/oe-kbuild-all/202507032322.5jzirIYw-lkp@intel.com/ All errors (new ones prefixed by >>): kernel/time/tick-sched.c: In function 'tick_setup_sched_timer': >> kernel/time/tick-sched.c:1577:44: error: 'CONFIG_TICK_SKEW_LIMIT' undeclared (first use in this function); did you mean 'CONFIG_TICK_ONESHOT'? 1577 | if (num_possible_cpus() >= CONFIG_TICK_SKEW_LIMIT) { | ^~~~~~~~~~~~~~~~~~~~~~ | CONFIG_TICK_ONESHOT kernel/time/tick-sched.c:1577:44: note: each undeclared identifier is reported only once for each function it appears in vim +1577 kernel/time/tick-sched.c 1566 1567 /** 1568 * tick_setup_sched_timer - setup the tick emulation timer 1569 * @hrtimer: whether to use the hrtimer or not 1570 */ 1571 void tick_setup_sched_timer(bool hrtimer) 1572 { 1573 struct tick_sched *ts = this_cpu_ptr(&tick_cpu_sched); 1574 1575 /* Figure out if we should skew the tick */ 1576 if (sched_skew_tick < 0) { > 1577 if (num_possible_cpus() >= CONFIG_TICK_SKEW_LIMIT) { 1578 sched_skew_tick = 1; 1579 pr_info("Tick skewed mode enabled. Possible cpus %u > %u\n", 1580 num_possible_cpus(), CONFIG_TICK_SKEW_LIMIT); 1581 } else 1582 sched_skew_tick = 0; 1583 } 1584 1585 /* Emulate tick processing via per-CPU hrtimers: */ 1586 hrtimer_setup(&ts->sched_timer, tick_nohz_handler, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD); 1587 1588 if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && hrtimer) 1589 tick_sched_flag_set(ts, TS_FLAG_HIGHRES); 1590 1591 /* Get the next period (per-CPU) */ 1592 hrtimer_set_expires(&ts->sched_timer, tick_init_jiffy_update()); 1593 1594 /* Offset the tick to avert 'jiffies_lock' contention. */ 1595 if (sched_skew_tick) { 1596 u64 offset = TICK_NSEC >> 1; 1597 do_div(offset, num_possible_cpus()); 1598 offset *= smp_processor_id(); 1599 hrtimer_add_expires_ns(&ts->sched_timer, offset); 1600 } else 1601 pr_info("Tick operating in synchronized mode.\n"); 1602 1603 1604 hrtimer_forward_now(&ts->sched_timer, TICK_NSEC); 1605 if (IS_ENABLED(CONFIG_HIGH_RES_TIMERS) && hrtimer) 1606 hrtimer_start_expires(&ts->sched_timer, HRTIMER_MODE_ABS_PINNED_HARD); 1607 else 1608 tick_program_event(hrtimer_get_expires(&ts->sched_timer), 1); 1609 tick_nohz_activate(ts); 1610 } 1611 -- 0-DAY CI Kernel Test Service https://github.com/intel/lkp-tests/wiki