Linux 5.5 Regression Bisected On AMD EPYC Rome
Tests for a future article.


5.5.0-rc3-pts: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.5.0-rc3-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

v5.4: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

8c39f71ee201: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

937d6eefc716: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

eb275167d186: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

48d6b4dd362c: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

2352923c753f: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

4672c2f2026d: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

01d1dff64662: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-pts (x86_64), Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

aef069a277dc: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-rc1-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

8321c2ecb2e8: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.4.0-rc1-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

341c1fda5e17: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.1.0-rc4-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

bf1d2ee7bc62: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.1.0-rc4-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

00e0590dbaec: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.1.0-rc4-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

8f21a6247525: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.1.0-rc4-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

bce4e7e9c45e: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.1.0-rc4-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080

apparmor=0: 

	Processor: 2 x AMD EPYC 7742 64-Core @ 2.25GHz (128 Cores / 256 Threads), Motherboard: AMD DAYTONA_X (RDY1001C BIOS), Chipset: AMD Starship/Matisse, Memory: 516096MB, Disk: 280GB INTEL SSDPE21D280GA + 256GB Micron_1100_MTFD, Graphics: ASPEED, Monitor: VE228, Network: 2 x Mellanox MT27710

	OS: Ubuntu 19.10, Kernel: 5.5.0-rc3-pts (x86_64) 20191229, Desktop: GNOME Shell 3.34.1, Display Server: X Server 1.20.5, Display Driver: modesetting 1.20.5, Compiler: GCC 9.2.1 20191008 + LLVM 9.0.0, File-System: ext4, Screen Resolution: 1920x1080


Hackbench
Count: 32 - Type: Process
Seconds < Lower Is Better
5.5.0-rc3-pts . 49.22 |=============================================
v5.4 .......... 15.28 |==============
8c39f71ee201 .. 12.59 |===========
937d6eefc716 .. 12.50 |===========
eb275167d186 .. 49.58 |=============================================
48d6b4dd362c .. 49.50 |=============================================
2352923c753f .. 12.35 |===========
4672c2f2026d .. 49.81 |=============================================
01d1dff64662 .. 12.54 |===========
aef069a277dc .. 14.95 |==============
8321c2ecb2e8 .. 15.50 |==============
341c1fda5e17 .. 61.63 |========================================================
bf1d2ee7bc62 .. 13.91 |=============
00e0590dbaec .. 14.27 |=============
8f21a6247525 .. 13.96 |=============
bce4e7e9c45e .. 47.79 |===========================================
apparmor=0 .... 12.27 |===========