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* [PATCH v3 0/4] Support SMT control on arm64
@ 2023-11-14  4:01 ` Yicong Yang
  0 siblings, 0 replies; 21+ messages in thread
From: Yicong Yang @ 2023-11-14  4:01 UTC (permalink / raw)
  To: catalin.marinas, will, sudeep.holla, linux-arm-kernel
  Cc: dietmar.eggemann, gregkh, rafael, jonathan.cameron, prime.zeng,
	linuxarm, yangyicong, linux-kernel

From: Yicong Yang <yangyicong@hisilicon.com>

The core CPU control framework supports runtime SMT control which
is not yet supported on arm64. Besides the general vulnerabilities
concerns we want this runtime control on our arm64 server for:

- better single CPU performance in some cases
- saving overall power consumption

This patchset implements it in the following aspects:

- implements the basic support in arch_topology driver
- support retrieve SMT thread number on OF based system
- support retrieve SMT thread number on ACPI based system
- select HOTPLUG_SMT for arm64

Tests has been done on our real ACPI based arm64 server and on
ACPI/OF based QEMU VMs.

The patchset is based on v6.7-rc1.

Change since v2:
- Detect SMT thread number at topology build from ACPI/DT, avoid looping CPUs
- Split patches into ACPI/OF/arch_topology path and enable the kconfig for arm64
Link: https://lore.kernel.org/linux-arm-kernel/20231010115335.13862-1-yangyicong@huawei.com/

Yicong Yang (4):
  arch_topology: Support basic SMT control for the driver
  arch_topology: Support SMT control for OF based system
  arm64: topology: Support SMT control on ACPI based system
  arm64: Kconfig: Enable HOTPLUG_SMT

 arch/arm64/Kconfig            |  1 +
 arch/arm64/kernel/topology.c  | 23 +++++++++++++++++++++
 drivers/base/arch_topology.c  | 39 +++++++++++++++++++++++++++++++++++
 include/linux/arch_topology.h |  9 ++++++++
 4 files changed, 72 insertions(+)

-- 
2.24.0


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^ permalink raw reply	[flat|nested] 21+ messages in thread
* Re: [PATCH v3 4/4] arm64: Kconfig: Enable HOTPLUG_SMT
  2023-11-14  4:01   ` Yicong Yang
  (?)
@ 2023-11-16  4:59 ` kernel test robot
  -1 siblings, 0 replies; 21+ messages in thread
From: kernel test robot @ 2023-11-15 11:22 UTC (permalink / raw)
  To: oe-kbuild; +Cc: lkp

:::::: 
:::::: Manual check reason: "only kconfig file changed"
:::::: 

BCC: lkp@intel.com
CC: oe-kbuild-all@lists.linux.dev
In-Reply-To: <20231114040110.54590-5-yangyicong@huawei.com>
References: <20231114040110.54590-5-yangyicong@huawei.com>
TO: Yicong Yang <yangyicong@huawei.com>
TO: catalin.marinas@arm.com
TO: will@kernel.org
TO: sudeep.holla@arm.com
TO: linux-arm-kernel@lists.infradead.org
CC: dietmar.eggemann@arm.com
CC: gregkh@linuxfoundation.org
CC: rafael@kernel.org
CC: jonathan.cameron@huawei.com
CC: prime.zeng@hisilicon.com
CC: linuxarm@huawei.com
CC: yangyicong@hisilicon.com
CC: linux-kernel@vger.kernel.org

Hi Yicong,

kernel test robot noticed the following build errors:

[auto build test ERROR on arm64/for-next/core]
[also build test ERROR on driver-core/driver-core-testing driver-core/driver-core-next driver-core/driver-core-linus arm/for-next kvmarm/next soc/for-next linus/master arm/fixes v6.7-rc1 next-20231115]
[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#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Yicong-Yang/arch_topology-Support-basic-SMT-control-for-the-driver/20231114-120544
base:   https://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-next/core
patch link:    https://lore.kernel.org/r/20231114040110.54590-5-yangyicong%40huawei.com
patch subject: [PATCH v3 4/4] arm64: Kconfig: Enable HOTPLUG_SMT
:::::: branch date: 31 hours ago
:::::: commit date: 31 hours ago
config: arm64-randconfig-002-20231115 (https://download.01.org/0day-ci/archive/20231115/202311151900.K9xc6Xqz-lkp@intel.com/config)
compiler: aarch64-linux-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20231115/202311151900.K9xc6Xqz-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 <lkp@intel.com>
| Closes: https://lore.kernel.org/r/202311151900.K9xc6Xqz-lkp@intel.com/

All errors (new ones prefixed by >>):

   kernel/cpu.c: In function 'cpuhp_smt_disable':
>> kernel/cpu.c:2687:23: error: implicit declaration of function 'cpu_down_maps_locked' [-Werror=implicit-function-declaration]
    2687 |                 ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
         |                       ^~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +/cpu_down_maps_locked +2687 kernel/cpu.c

dc8d37ed304eee Arnd Bergmann    2019-12-10  2672  
dc8d37ed304eee Arnd Bergmann    2019-12-10  2673  int cpuhp_smt_disable(enum cpuhp_smt_control ctrlval)
dc8d37ed304eee Arnd Bergmann    2019-12-10  2674  {
dc8d37ed304eee Arnd Bergmann    2019-12-10  2675  	int cpu, ret = 0;
dc8d37ed304eee Arnd Bergmann    2019-12-10  2676  
dc8d37ed304eee Arnd Bergmann    2019-12-10  2677  	cpu_maps_update_begin();
dc8d37ed304eee Arnd Bergmann    2019-12-10  2678  	for_each_online_cpu(cpu) {
dc8d37ed304eee Arnd Bergmann    2019-12-10  2679  		if (topology_is_primary_thread(cpu))
dc8d37ed304eee Arnd Bergmann    2019-12-10  2680  			continue;
38253464bc821d Michael Ellerman 2023-07-05  2681  		/*
38253464bc821d Michael Ellerman 2023-07-05  2682  		 * Disable can be called with CPU_SMT_ENABLED when changing
38253464bc821d Michael Ellerman 2023-07-05  2683  		 * from a higher to lower number of SMT threads per core.
38253464bc821d Michael Ellerman 2023-07-05  2684  		 */
38253464bc821d Michael Ellerman 2023-07-05  2685  		if (ctrlval == CPU_SMT_ENABLED && cpu_smt_thread_allowed(cpu))
38253464bc821d Michael Ellerman 2023-07-05  2686  			continue;
dc8d37ed304eee Arnd Bergmann    2019-12-10 @2687  		ret = cpu_down_maps_locked(cpu, CPUHP_OFFLINE);
dc8d37ed304eee Arnd Bergmann    2019-12-10  2688  		if (ret)
dc8d37ed304eee Arnd Bergmann    2019-12-10  2689  			break;
dc8d37ed304eee Arnd Bergmann    2019-12-10  2690  		/*
dc8d37ed304eee Arnd Bergmann    2019-12-10  2691  		 * As this needs to hold the cpu maps lock it's impossible
dc8d37ed304eee Arnd Bergmann    2019-12-10  2692  		 * to call device_offline() because that ends up calling
dc8d37ed304eee Arnd Bergmann    2019-12-10  2693  		 * cpu_down() which takes cpu maps lock. cpu maps lock
dc8d37ed304eee Arnd Bergmann    2019-12-10  2694  		 * needs to be held as this might race against in kernel
dc8d37ed304eee Arnd Bergmann    2019-12-10  2695  		 * abusers of the hotplug machinery (thermal management).
dc8d37ed304eee Arnd Bergmann    2019-12-10  2696  		 *
dc8d37ed304eee Arnd Bergmann    2019-12-10  2697  		 * So nothing would update device:offline state. That would
dc8d37ed304eee Arnd Bergmann    2019-12-10  2698  		 * leave the sysfs entry stale and prevent onlining after
dc8d37ed304eee Arnd Bergmann    2019-12-10  2699  		 * smt control has been changed to 'off' again. This is
dc8d37ed304eee Arnd Bergmann    2019-12-10  2700  		 * called under the sysfs hotplug lock, so it is properly
dc8d37ed304eee Arnd Bergmann    2019-12-10  2701  		 * serialized against the regular offline usage.
dc8d37ed304eee Arnd Bergmann    2019-12-10  2702  		 */
dc8d37ed304eee Arnd Bergmann    2019-12-10  2703  		cpuhp_offline_cpu_device(cpu);
dc8d37ed304eee Arnd Bergmann    2019-12-10  2704  	}
dc8d37ed304eee Arnd Bergmann    2019-12-10  2705  	if (!ret)
dc8d37ed304eee Arnd Bergmann    2019-12-10  2706  		cpu_smt_control = ctrlval;
dc8d37ed304eee Arnd Bergmann    2019-12-10  2707  	cpu_maps_update_done();
dc8d37ed304eee Arnd Bergmann    2019-12-10  2708  	return ret;
dc8d37ed304eee Arnd Bergmann    2019-12-10  2709  }
dc8d37ed304eee Arnd Bergmann    2019-12-10  2710  

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

^ permalink raw reply	[flat|nested] 21+ messages in thread

end of thread, other threads:[~2023-11-20  3:47 UTC | newest]

Thread overview: 21+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-11-14  4:01 [PATCH v3 0/4] Support SMT control on arm64 Yicong Yang
2023-11-14  4:01 ` Yicong Yang
2023-11-14  4:01 ` [PATCH v3 1/4] arch_topology: Support basic SMT control for the driver Yicong Yang
2023-11-14  4:01   ` Yicong Yang
2023-11-14 13:42   ` kernel test robot
2023-11-14 13:42     ` kernel test robot
2023-11-15 15:23   ` kernel test robot
2023-11-15 15:23     ` kernel test robot
2023-11-20  3:29     ` Yicong Yang
2023-11-20  3:29       ` Yicong Yang
2023-11-14  4:01 ` [PATCH v3 2/4] arch_topology: Support SMT control for OF based system Yicong Yang
2023-11-14  4:01   ` Yicong Yang
2023-11-14  4:01 ` [PATCH v3 3/4] arm64: topology: Support SMT control on ACPI " Yicong Yang
2023-11-14  4:01   ` Yicong Yang
2023-11-14  4:01 ` [PATCH v3 4/4] arm64: Kconfig: Enable HOTPLUG_SMT Yicong Yang
2023-11-14  4:01   ` Yicong Yang
  -- strict thread matches above, loose matches on Subject: below --
2023-11-15 11:22 kernel test robot
2023-11-16  4:59 ` kernel test robot
2023-11-16  4:59 ` kernel test robot
2023-11-20  3:27 ` Yicong Yang
2023-11-20  3:27   ` Yicong Yang

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