Intel Linux Kernel Power Regression
Investigating a potential power issue between Linux 3.15 and 3.16 kernels... Benchmarks by Michael Larabel for a future article on Phoronix.com.


Linux 3.13: 

	Processor: Intel Core i7-3517U @ 3.00GHz (4 Cores), Motherboard: ASUS UX32VDA v1.0, Chipset: Intel 3rd Gen Core DRAM, Memory: 4096MB, Disk: 2 x 128GB SanDisk SD5SF212, Graphics: Intel HD 4000 512MB (1150MHz), Audio: Realtek ALC269VB, Network: Intel Centrino Advanced-N 6235

	OS: Ubuntu 14.04, Kernel: 3.13.0-031300-generic (x86_64), Desktop: GNOME Shell 3.10.4, Display Server: X Server 1.15.1, Display Driver: intel 2.99.910, OpenGL: 3.3 Mesa 10.1.3, Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 1920x1080

Linux 3.14: 

	Processor: Intel Core i7-3517U @ 3.00GHz (4 Cores), Motherboard: ASUS UX32VDA v1.0, Chipset: Intel 3rd Gen Core DRAM, Memory: 4096MB, Disk: 2 x 128GB SanDisk SD5SF212, Graphics: Intel HD 4000 512MB (1150MHz), Audio: Realtek ALC269VB, Network: Intel Centrino Advanced-N 6235

	OS: Ubuntu 14.04, Kernel: 3.14.0-031400-generic (x86_64), Desktop: GNOME Shell 3.10.4, Display Server: X Server 1.15.1, Display Driver: intel 2.99.910, OpenGL: 3.3 Mesa 10.1.3, Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 1920x1080

Linux 3.15: 

	Processor: Intel Core i7-3517U @ 3.00GHz (4 Cores), Motherboard: ASUS UX32VDA v1.0, Chipset: Intel 3rd Gen Core DRAM, Memory: 4096MB, Disk: 2 x 128GB SanDisk SD5SF212, Graphics: Intel HD 4000 512MB (1150MHz), Audio: Realtek ALC269VB, Network: Intel Centrino Advanced-N 6235

	OS: Ubuntu 14.04, Kernel: 3.15.0-031500-generic (x86_64), Desktop: GNOME Shell 3.10.4, Display Server: X Server 1.15.1, Display Driver: intel 2.99.910, OpenGL: 3.3 Mesa 10.1.3, Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 1920x1080

Linux 3.16: 

	Processor: Intel Core i7-3517U @ 3.00GHz (4 Cores), Motherboard: ASUS UX32VDA v1.0, Chipset: Intel 3rd Gen Core DRAM, Memory: 4096MB, Disk: 2 x 128GB SanDisk SD5SF212, Graphics: Intel HD 4000 512MB (1150MHz), Audio: Realtek ALC269VB, Network: Intel Centrino Advanced-N 6235

	OS: Ubuntu 14.04, Kernel: 3.16.0-031600-generic (x86_64), Desktop: GNOME Shell 3.10.4, Display Server: X Server 1.15.1, Display Driver: intel 2.99.910, OpenGL: 3.3 Mesa 10.1.3, Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 1920x1080

Linux 3.17 Git: 

	Processor: Intel Core i7-3517U @ 3.00GHz (4 Cores), Motherboard: ASUS UX32VDA v1.0, Chipset: Intel 3rd Gen Core DRAM, Memory: 4096MB, Disk: 2 x 128GB SanDisk SD5SF212, Graphics: Intel HD 4000 512MB (1150MHz), Audio: Realtek ALC269VB, Network: Intel Centrino Advanced-N 6235

	OS: Ubuntu 14.04, Kernel: 3.17.0-999-generic (x86_64), Desktop: GNOME Shell 3.10.4, Display Server: X Server 1.15.1, Display Driver: intel 2.99.910, OpenGL: 3.3 Mesa 10.1.3, Compiler: GCC 4.8.2, File-System: ext4, Screen Resolution: 1920x1080


LAME MP3 Encoding 3.99.3
WAV To MP3
Seconds < Lower Is Better
Linux 3.13 ..... 28.32 |=======================================================
Linux 3.14 ..... 23.84 |==============================================
Linux 3.15 ..... 28.29 |=======================================================
Linux 3.16 ..... 17.10 |=================================
Linux 3.17 Git . 17.06 |=================================


Xonotic 0.7
Resolution: 1920 x 1080 - Effects Quality: High
Frames Per Second > Higher Is Better
Linux 3.13 ..... 58.38 |======================================================
Linux 3.14 ..... 58.45 |======================================================
Linux 3.15 ..... 58.70 |=======================================================
Linux 3.16 ..... 59.01 |=======================================================
Linux 3.17 Git . 59.14 |=======================================================


Xonotic 0.7
System Power Consumption Monitor
Milliwatts < Lower Is Better
Linux 3.13 ..... MIN: 15636  AVG: 35070  MAX: 38546 
Linux 3.14 ..... MIN: 15406  AVG: 34179  MAX: 37399 
Linux 3.15 ..... MIN: 15103  AVG: 33032  MAX: 36667 
Linux 3.16 ..... MIN: 15273  AVG: 34164  MAX: 36674 
Linux 3.17 Git . MIN: 15554  AVG: 34965  MAX: 37939 


LAME MP3 Encoding 3.99.3
System Power Consumption Monitor
Milliwatts < Lower Is Better
Linux 3.13 ..... MIN: 15229  AVG: 19783  MAX: 21578 
Linux 3.14 ..... MIN: 15044  AVG: 20350  MAX: 25263 
Linux 3.15 ..... MIN: 14718  AVG: 19065  MAX: 20779 
Linux 3.16 ..... MIN: 14985  AVG: 23011  MAX: 27972 
Linux 3.17 Git . MIN: 15369  AVG: 23273  MAX: 26122 


Timed Idle
System Power Consumption Monitor
Milliwatts < Lower Is Better
Linux 3.13 ..... MIN: 14681  AVG: 15128  MAX: 16768 
Linux 3.14 ..... MIN: 14467  AVG: 14878  MAX: 16339 
Linux 3.15 ..... MIN: 6070   AVG: 14489  MAX: 16605 
Linux 3.16 ..... MIN: 14452  AVG: 14808  MAX: 16257 
Linux 3.17 Git . MIN: 14600  AVG: 14930  MAX: 15591 


System Power Consumption Monitor
Phoronix Test Suite System Monitoring
Milliwatts
Linux 3.13 ..... MIN: 14681  AVG: 27476  MAX: 38546 
Linux 3.14 ..... MIN: 14467  AVG: 27106  MAX: 37399 
Linux 3.15 ..... MIN: 6070   AVG: 26022  MAX: 36667 
Linux 3.16 ..... MIN: 14259  AVG: 27550  MAX: 36674 
Linux 3.17 Git . MIN: 14600  AVG: 28112  MAX: 37939