BogoMIPS reduced with kernel 6.3.2 and 6.3.3

[hackmack]

Hi,

does anyone knows why BogoMIPS and RAID throughput changed with kernel 6.3.2 & 6.3.3?

May 10 20:24:39 dallifix kernel: Linux version 6.3.1 (root@dallifix) (gcc (Gentoo 12.2.1_p20230304 p13) 12.2.1 20230304, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Tue May 9 22:05:27 CEST 2023
May 10 20:24:39 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.24 BogoMIPS (lpj=24941220)
May 10 20:24:39 dallifix kernel: smpboot: Total of 64 processors activated (319307.76 BogoMIPS)
May 10 20:24:39 dallifix kernel: raid6: using algorithm avx2x2 gen() 28788 MB/s

May 12 15:51:28 dallifix kernel: Linux version 6.3.2 (root@dallifix) (gcc (Gentoo 12.2.1_p20230428-r1 p2) 12.2.1 20230428, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Fri May 12 14:40:41 CEST 2023
May 12 15:51:28 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.08 BogoMIPS (lpj=24940400)
May 12 15:51:28 dallifix kernel: smpboot: Total of 64 processors activated (189577.45 BogoMIPS)
May 12 15:51:28 dallifix kernel: raid6: using algorithm avx2x2 gen() 5386 MB/s

May 19 00:39:43 dallifix kernel: Linux version 6.3.3 (root@dallifix) (gcc (Gentoo 12.2.1_p20230428-r1 p2) 12.2.1 20230428, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Wed May 17 16:45:00 CEST 2023
May 19 00:39:43 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.45 BogoMIPS (lpj=24942280)
May 19 00:39:43 dallifix kernel: smpboot: Total of 64 processors activated (196200.88 BogoMIPS)
May 19 00:39:43 dallifix kernel: raid6: using algorithm avx2x4 gen() 6263 MB/s

Back to "normal" - no hardware "damage"
May 19 01:11:53 dallifix kernel: Linux version 6.3.1 (root@dallifix) (gcc (Gentoo 12.2.1_p20230304 p13) 12.2.1 20230304, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Tue May 9 22:05:27 CEST 2023
May 19 01:11:53 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.42 BogoMIPS (lpj=24942110)
May 19 01:11:53 dallifix kernel: smpboot: Total of 64 processors activated (319281.46 BogoMIPS)
May 19 01:11:53 dallifix kernel: raid6: using algorithm avx2x2 gen() 27445 MB/s

thx

[hackmack]

Obviously, 6.3.4 and 6.3.5 have the same problems ...

I don't understand that the BogoMIPS of one CPU is always the same but when in impress_friends() BogoMIPS for all CPUs is summed the value is lower.

May 25 18:33:56 dallifix kernel: Linux version 6.3.4 (root@dallifix) (gcc (Gentoo 12.2.1_p20230428-r1 p2) 12.2.1 20230428, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Thu May 25 18:21:11 CEST 2023
May 25 18:33:56 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.80 BogoMIPS (lpj=24944030)
May 25 18:33:56 dallifix kernel: smpboot: Total of 64 processors activated (274683.94 BogoMIPS)
May 25 18:33:56 dallifix kernel: raid6: using algorithm avx2x4 gen() 19653 MB/s

May 30 22:26:38 dallifix kernel: Linux version 6.3.5 (root@dallifix) (gcc (Gentoo 12.2.1_p20230428-r1 p2) 12.2.1 20230428, GNU ld (Gentoo 2.39 p6) 2.39.0) #1 SMP Tue May 30 22:04:34 CEST 2023
May 30 22:26:38 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.77 BogoMIPS (lpj=24943860)
May 30 22:26:38 dallifix kernel: smpboot: Total of 64 processors activated (219201.33 BogoMIPS)
May 30 22:26:38 dallifix kernel: raid6: using algorithm avx2x2 gen() 10766 MB/s

Back to 6.3.1 - with expected values
May 30 22:37:21 dallifix kernel: Linux version 6.3.1 (root@dallifix) (gcc (Gentoo 12.2.1_p20230428-r1 p2) 12.2.1 20230428, GNU ld (Gentoo 2.39 p6) 2.39.0) #2 SMP Tue May 30 22:31:55 CEST 2023
May 30 22:37:21 dallifix kernel: Calibrating delay loop (skipped), value calculated using timer frequency.. 4988.14 BogoMIPS (lpj=24940710)
May 30 22:37:21 dallifix kernel: smpboot: Total of 64 processors activated (319298.87 BogoMIPS)
May 30 22:37:21 dallifix kernel: raid6: using algorithm avx2x2 gen() 28808 MB/s

[szatox]

Bogomips tells you how many times per second your cpu can do nothing.
Don't worry about that number, unless you see a performance drop somewhere else.

No idea about your RAID's numbers, but you could test it with iozone or something similar and see whether or not there is a problem.