# Phenom BogoMIPS

## wilf

Hi,

I have just installed my Gigabyte GA-MA790FX-DQ6, and after a few hiccoughs she is up and running. 2.6.18/OpenVZ kernel wouldn't see the on-board Realtek 8111b's, but that's OK as I have too many spare NICS, two of which have been pressed into service.

Just a quick query, I thought I'd have a quick look at the rough BogoMIPS guide in /var/log/dmesg  for my new HT3 Phenom, and look what it turns up:-

```
Your BIOS doesn't leave a aperture memory hole

Please enable the IOMMU option in the BIOS setup

This costs you 64 MB of RAM

Mapping aperture over 65536 KB of RAM @ c000000

Memory: 8158284k/9175040k available (4305k kernel code, 228528k reserved, 1654k data, 236k init)

Calibrating delay using timer specific routine.. 5027.10 BogoMIPS (lpj=2513552)

Mount-cache hash table entries: 256

CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)

CPU: L2 Cache: 512K (64 bytes/line)

using mwait in idle threads.

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 0

Freeing SMP alternatives: 44k freed

ACPI: Core revision 20060707

Page beancounter hash is 1048576 entries.

activating NMI Watchdog ... done.

Using local APIC timer interrupts.

result 12557085

Detected 12.557 MHz APIC timer.

Booting processor 1/4 APIC 0x1

Initializing CPU#1

Calibrating delay using timer specific routine.. 2511.43 BogoMIPS (lpj=1255717)

CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)

CPU: L2 Cache: 512K (64 bytes/line)

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 1

AMD Phenom(tm) 9850 Quad-Core Processor stepping 03

CPU 1: Syncing TSC to CPU 0.

CPU 1: synchronized TSC with CPU 0 (last diff 12 cycles, maxerr 739 cycles)

Booting processor 2/4 APIC 0x2

Initializing CPU#2

Calibrating delay using timer specific routine.. 2513.11 BogoMIPS (lpj=1256556)

CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)

CPU: L2 Cache: 512K (64 bytes/line)

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 3

AMD Phenom(tm) 9850 Quad-Core Processor stepping 03

CPU 2: Syncing TSC to CPU 0.

CPU 2: synchronized TSC with CPU 0 (last diff -2 cycles, maxerr 755 cycles)

Booting processor 3/4 APIC 0x3

Initializing CPU#3

Calibrating delay using timer specific routine.. 2514.00 BogoMIPS (lpj=1257000)

CPU: L1 I Cache: 64K (64 bytes/line), D cache 64K (64 bytes/line)

CPU: L2 Cache: 512K (64 bytes/line)

CPU: Physical Processor ID: 0

CPU: Processor Core ID: 2

AMD Phenom(tm) 9850 Quad-Core Processor stepping 03

CPU 3: Syncing TSC to CPU 0.

CPU 3: synchronized TSC with CPU 0 (last diff -6 cycles, maxerr 730 cycles)

Brought up 4 CPUs

testing NMI watchdog ... CPU#0: NMI appears to be stuck (0->0)!

migration_cost=53
```

The BIOS errors I'll look into, but 5027.10 BogoMIPS sounds like what I'd expect from a 9850 for the first core,  what about the others at only around 25xx BogoMIPS? Is this along the lines of the otehr cores are power saving?

Best Regards, Paul.

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## poly_poly-man

bogomips are just that - BOGUS mips.

their values are meaningless... it means nothing.

Check /proc/cpuinfo (while running) to make sure all the frequencies are too your liking.

run a good benchmark if you aren't satisfied.

poly-p man

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## wilf

Yes, I see that. Wikipedia sums it up nicely.

 *Quote:*   

> BogoMips can be used to see whether it is in the proper range for the particular processor, its clock frequency, and the potentially present CPU cache. It is not usable for performance comparison between different CPUs

 

This is still a bizarre result from a test on four identical processors, and I wondered at the reason. 

```
Calibrating delay using timer specific routine.. 5027.10 BogoMIPS (lpj=2513552)

Calibrating delay using timer specific routine.. 2511.43 BogoMIPS (lpj=1255717)

Calibrating delay using timer specific routine.. 2513.11 BogoMIPS (lpj=1256556)

Calibrating delay using timer specific routine.. 2514.00 BogoMIPS (lpj=1257000)
```

I am happy with the performance, it's doing just what I want.

Best Regards, Paul.

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## eccerr0r

Actually I'm curious...

While a few bogomips difference between cores on the same die may happen due to scheduling, a 2:1 difference seems somewhat bad unless it somehow kicked the core to power save mode while running on the other cores (??!)...  My Intel C2D and C2Q machines' bogomips for each core are roughly similar to each other; I don't see that much of a variation - after all, the cores should be identical to each other.

```
blc@ouka:~$ cat /proc/cpuinfo |grep bogo

bogomips        : 5381.54

bogomips        : 5322.69

```

Perhaps firmware is not setting up the registers for each core properly?  May want to see if new firmware fixes the issue.  But yes, try benchmarks, specifically parallelizable ones, and verify you get 4x performance to 1-thread.

----------

