benchmark anomalies > hpl (linpack)

dummy@example.com (kapqa) — Fri, 05 Sep 2025 14:32:03 +0000

Hello ,

must have gotten watched too many "educational" video,

now tested this benchmark called "linpack" on the main computer running Linux in two flavors

1 > Kubuntu 25.04 (with amdgpu, via amdgpu-install)
2 > Devuan 5.0 (with firmware-amd-graphics)

the computer is as such the same, just the OS are sitting on two different SSD (one is PCIe gen 4x4 for Kubuntu , one is PCIe gen 3x4 for Devuan)

the results of running the benchmark are quite different;

for Kubuntu the result is around 800 Gigaflops?
for Devuan 5.0 (or Linux Mint) the benchmark would top out at around 200 Gigaflops?

This result seem rather questionalble to me so i wonder what one should make out of it?

The install is via

phoronix-test-suite.deb and then install from there hpl and running it through the suite (no configuratin needed).

for Kubnut 25.04

Evaluating External Test Dependencies ....................................................................................................................
Phoronix Test Suite v10.8.4
Installed: pts/hpl-1.0.0

OPERATING SYSTEM:       Ubuntu 25.04
    Kernel:               6.14.0-29-generic (x86_64)                                                                                                               
    Desktop:              KDE Plasma 6.3.6                                                                                                                         
    Display Server:       X Server 1.21.1.16                                                                                                                       
    Compiler:             GCC 14.2.0 + Clang 20.1.2                                                                                                                
    Security:             gather_data_sampling: Not affected                                                                                                       
                          + ghostwrite: Not affected                                                                                                               
                          + indirect_target_selection: Not affected                                                                                                
                          + itlb_multihit: Not affected                                                                                                            
                          + l1tf: Not affected                                                                                                                     
                          + mds: Not affected                                                                                                                      
                          + meltdown: Not affected                                                                                                                 
                          + mmio_stale_data: Not affected                                                                                                          
                          + reg_file_data_sampling: Not affected                                                                                                   
                          + retbleed: Not affected                                                                                                                 
                          + spec_rstack_overflow: Mitigation of IBPB on VMEXIT only                                                                                
                          + spec_store_bypass: Mitigation of SSB disabled via prctl                                                                                
                          + spectre_v1: Mitigation of usercopy/swapgs barriers and __user pointer sanitization                                                     
                          + spectre_v2: Mitigation of Enhanced / Automatic IBRS; IBPB: conditional; STIBP: always-on; PBRSB-eIBRS: Not affected; BHI: Not affected 
                          + srbds: Not affected                                                                                                                    
                          + tsx_async_abort: Not affected

Current Description: AMD Ryzen 7 9700X 8-Core testing with a ASUS PRIME X670-P (3278 BIOS) and Sapphire AMD Radeon RX 7600 8GB on Ubuntu 25.04 via the Phoronix Test Suite.

New Description: 

HPL Linpack 2.3:
    pts/hpl-1.0.0
    Test 1 of 1
    Test Profile Status:          Experimental  
    Estimated Trial Run Count:    3                     
    Estimated Time To Completion: 6 Minutes [12:37 UTC] 
        Started Run 1 @ 12:31:16
        Started Run 2 @ 12:33:15
        Started Run 3 @ 12:35:14

    Test Results:
        798.66
        799.4
        798.8

    Average: 798.95 GFLOPS
    Deviation: 0.05%

for Devuan 5.0 "Daedalus"

sudo phoronix-test-suite run hpl
Phoronix Test Suite v10.8.4

OPERATING SYSTEM:       Devuan 5
    Kernel:               6.1.0-38-amd64 (x86_64)                                                                                                                  
    Desktop:              Cinnamon 5.6.8                                                                                                                           
    Display Server:       X Server 1.21.1.7                                                                                                                        
    Compiler:             GCC 12.2.0                                                                                                                               
    Security:             gather_data_sampling: Not affected                                                                                                       
                          + indirect_target_selection: Not affected                                                                                                
                          + itlb_multihit: Not affected                                                                                                            
                          + l1tf: Not affected                                                                                                                     
                          + mds: Not affected                                                                                                                      
                          + meltdown: Not affected                                                                                                                 
                          + mmio_stale_data: Not affected                                                                                                          
                          + reg_file_data_sampling: Not affected                                                                                                   
                          + retbleed: Not affected                                                                                                                 
                          + spec_rstack_overflow: Not affected                                                                                                     
                          + spec_store_bypass: Mitigation of SSB disabled via prctl                                                                                
                          + spectre_v1: Mitigation of usercopy/swapgs barriers and __user pointer sanitization                                                     
                          + spectre_v2: Mitigation of Enhanced / Automatic IBRS; IBPB: conditional; STIBP: always-on; PBRSB-eIBRS: Not affected; BHI: Not affected 
                          + srbds: Not affected                                                                                                                    
                          + tsa: Not affected                                                                                                                      
                          + tsx_async_abort: Not affected

Enter a name for the result file: devuan 5.0 / firmware-amd-graphics
    Enter a unique name to describe this test run / configuration: 

If desired, enter a new description below to better describe this result set / system configuration under test.
Press ENTER to proceed without changes.

Current Description: AMD Ryzen 7 9700X 8-Core testing with a ASUS PRIME X670-P (3278 BIOS) and Sapphire AMD Radeon RX 7700S/7600S 8GB on Devuan 5 via the Phoronix Test Suite.

New Description: 

        [Performance Tip] The CPU scaling governor is currently not set to performance. It's possible to obtain greater performance if using the performance governor.

        To change behavior, run: 

        echo performance | tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor

        Reference: https://openbenchmarking.org/result/1706268-TR-CPUGOVERN32

        To stop showing performance tips, run: phoronix-test-suite unload-module perf_tips

        Continuing in 5 seconds or press CTRL-C to stop the testing process.

HPL Linpack 2.3:
    pts/hpl-1.0.0
    Test 1 of 1
    Test Profile Status:          Experimental   
    Estimated Trial Run Count:    3                      
    Estimated Time To Completion: 21 Minutes [14:45 UTC] 
        Started Run 1 @ 14:25:02
        Started Run 2 @ 14:31:40
        Started Run 3 @ 14:38:27
        Started Run 4 @ 14:44:48 *
        Started Run 5 @ 14:51:43 *
        Started Run 6 @ 14:58:29 *
        Started Run 7 @ 15:05:16 *
        Started Run 8 @ 15:12:00 *
        Started Run 9 @ 15:18:51 *

    Test Results:
        217.92
        213.63
        228.29
        208.93
        213.66
        212.91
        215.11
        210.84
        213.59

    Average: 214.99 GFLOPS
 Deviation: 2.60%
    Samples: 9

Dev1 Galaxy Forum / benchmark anomalies > hpl (linpack)

benchmark anomalies > hpl (linpack)