BogoMIPS are not consistent in SMP

[Costin Grigoras]

When allocating more than 1 cpu to a guest, the bogomips is ok only for the first one. For example:

# cat /proc/cpuinfo | grep -E "processor|MHz|bogomips"
processor       : 0
cpu MHz         : 2772.361
bogomips        : 5544.72
processor       : 1
cpu MHz         : 2772.361
bogomips        : 326.15
processor       : 2
cpu MHz         : 2772.361
bogomips        : 345.29
processor       : 3
cpu MHz         : 2772.361
bogomips        : 347.57

Relevant dmesg messages:

# dmesg | grep -i bogo
Calibrating delay loop (skipped), value calculated using timer frequency.. 5544.72 BogoMIPS (lpj=27723610)
Calibrating delay using timer specific routine.. 326.15 BogoMIPS (lpj=1630777)
Calibrating delay using timer specific routine.. 345.29 BogoMIPS (lpj=1726479)
Calibrating delay using timer specific routine.. 347.57 BogoMIPS (lpj=1737883)
Total of 4 processors activated (6563.74 BogoMIPS).

[Sander van Leeuwen]

Fixed a few hours ago.

[Costin Grigoras]

Just tried 3.0.2 and while it's somehow better than before, the problem is in fact still there:

# dmesg | grep -i bogo
Calibrating delay loop (skipped), value calculated using timer frequency.. 5541.02 BogoMIPS (lpj=27705110)
Calibrating delay using timer specific routine.. 5549.30 BogoMIPS (lpj=27746504)
Calibrating delay loop... 52.32 BogoMIPS (lpj=261632)
Calibrating delay using timer specific routine.. 5548.32 BogoMIPS (lpj=27741612)
Total of 4 processors activated (16690.97 BogoMIPS).

[Costin Grigoras]

And two other guests, same host, with various wrong values:

Calibrating delay loop (skipped), value calculated using timer frequency.. 5527.58 BogoMIPS (lpj=27637940)
Calibrating delay using timer specific routine.. 14963.07 BogoMIPS (lpj=74815370)
Calibrating delay using timer specific routine.. 5475.00 BogoMIPS (lpj=27375016)
Calibrating delay using timer specific routine.. 5319.95 BogoMIPS (lpj=26599788)
Total of 4 processors activated (31285.62 BogoMIPS).

[    0.010021] Calibrating delay loop (skipped), value calculated using timer frequency.. 5558.70 BogoMIPS (lpj=27793520)
[    0.010000] Calibrating delay loop... 5544.34 BogoMIPS (lpj=27721728)
[    0.010000] Calibrating delay using timer specific routine.. 8240.36 BogoMIPS (lpj=41201808)
[    0.010000] Calibrating delay using timer specific routine.. 3830.29 BogoMIPS (lpj=19151482)
[    2.352890] Total of 4 processors activated (23173.70 BogoMIPS).

[Frank Mehnert]

Should be much better with the new paravirtualization interface introduced with VBox 5.0.