* bogomips discrepancy on Intel Core2 Quad CPU
@ 2007-09-03 8:06 Bauke Jan Douma
2007-09-03 14:47 ` Bill Davidsen
0 siblings, 1 reply; 4+ messages in thread
From: Bauke Jan Douma @ 2007-09-03 8:06 UTC (permalink / raw)
To: linux-kernel
[-- Attachment #1: Type: text/plain, Size: 272 bytes --]
$> uname -a
Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007 i686 GNU/Linux
$> cat /proc/cpuinfo | grep bogomips
bogomips : 4813.46
bogomips : 4810.91
bogomips : 4810.91
bogomips : 10583.94
The latter seems way off base.
Prod me for more info.
bjd
[-- Attachment #2: cpuinfo-full.txt --]
[-- Type: text/plain, Size: 2369 bytes --]
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU @ 2.40GHz
stepping : 7
cpu MHz : 2405.551
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 0
cpu cores : 4
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4813.46
clflush size : 64
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU @ 2.40GHz
stepping : 7
cpu MHz : 2405.551
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 1
cpu cores : 4
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4810.91
clflush size : 64
processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU @ 2.40GHz
stepping : 7
cpu MHz : 2405.551
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 2
cpu cores : 4
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 4810.91
clflush size : 64
processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 15
model name : Intel(R) Core(TM)2 Quad CPU @ 2.40GHz
stepping : 7
cpu MHz : 2405.551
cache size : 4096 KB
physical id : 0
siblings : 4
core id : 3
cpu cores : 4
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 10
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc pni monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr lahf_lm
bogomips : 10583.94
clflush size : 64
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: bogomips discrepancy on Intel Core2 Quad CPU
2007-09-03 8:06 bogomips discrepancy on Intel Core2 Quad CPU Bauke Jan Douma
@ 2007-09-03 14:47 ` Bill Davidsen
2007-09-03 15:44 ` Justin Piszcz
2007-09-08 23:03 ` Bauke Jan Douma
0 siblings, 2 replies; 4+ messages in thread
From: Bill Davidsen @ 2007-09-03 14:47 UTC (permalink / raw)
To: bjdouma; +Cc: linux-kernel
Bauke Jan Douma wrote:
> $> uname -a
> Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007
> i686 GNU/Linux
>
> $> cat /proc/cpuinfo | grep bogomips
> bogomips : 4813.46
> bogomips : 4810.91
> bogomips : 4810.91
> bogomips : 10583.94
>
> The latter seems way off base.
> Prod me for more info.
>
I see this occasionally on a dual, speedstep (or similar) finds a way to
throttle down the cores under light load. I suspect that if you load the
system:
for n in 1 2 3 4; do
nice -19 bash -c 'while true; do a=$RANDOM; done' &
done
Then you should see your bogomips rise on all cores.
> bjd
[... copy of output snipped, see the O.P. ...]
--
Bill Davidsen <davidsen@tmr.com>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: bogomips discrepancy on Intel Core2 Quad CPU
2007-09-03 14:47 ` Bill Davidsen
@ 2007-09-03 15:44 ` Justin Piszcz
2007-09-08 23:03 ` Bauke Jan Douma
1 sibling, 0 replies; 4+ messages in thread
From: Justin Piszcz @ 2007-09-03 15:44 UTC (permalink / raw)
To: Bill Davidsen; +Cc: bjdouma, linux-kernel
On Mon, 3 Sep 2007, Bill Davidsen wrote:
> Bauke Jan Douma wrote:
>> $> uname -a
>> Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007 i686
>> GNU/Linux
>>
>> $> cat /proc/cpuinfo | grep bogomips
>> bogomips : 4813.46
>> bogomips : 4810.91
>> bogomips : 4810.91
>> bogomips : 10583.94
>>
>> The latter seems way off base.
>> Prod me for more info.
>>
> I see this occasionally on a dual, speedstep (or similar) finds a way to
> throttle down the cores under light load. I suspect that if you load the
> system:
>
> for n in 1 2 3 4; do
> nice -19 bash -c 'while true; do a=$RANDOM; done' &
> done
>
> Then you should see your bogomips rise on all cores.
>
>
>> bjd
>
> [... copy of output snipped, see the O.P. ...]
>
> --
> Bill Davidsen <davidsen@tmr.com>
> "We have more to fear from the bungling of the incompetent than from
> the machinations of the wicked." - from Slashdot
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>
$ uname -a
Linux p34.internal.lan 2.6.22 #2 SMP Mon Jul 16 18:40:31 EDT 2007 x86_64
GNU/Linux
$ cat /proc/cpuinfo | grep bogomips
bogomips : 4797.72
bogomips : 4795.16
bogomips : 4795.21
bogomips : 4795.19
Mine is fine, not using any speedstep here.
Justin.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: bogomips discrepancy on Intel Core2 Quad CPU
2007-09-03 14:47 ` Bill Davidsen
2007-09-03 15:44 ` Justin Piszcz
@ 2007-09-08 23:03 ` Bauke Jan Douma
1 sibling, 0 replies; 4+ messages in thread
From: Bauke Jan Douma @ 2007-09-08 23:03 UTC (permalink / raw)
To: Bill Davidsen; +Cc: linux-kernel
Bill Davidsen wrote on 03-09-07 16:47:
> Bauke Jan Douma wrote:
>> $> uname -a
>> Linux skyscraper 2.6.22.5 #7 SMP PREEMPT Sun Sep 2 12:12:25 CEST 2007
>> i686 GNU/Linux
>>
>> $> cat /proc/cpuinfo | grep bogomips
>> bogomips : 4813.46
>> bogomips : 4810.91
>> bogomips : 4810.91
>> bogomips : 10583.94
>>
>> The latter seems way off base.
>> Prod me for more info.
>>
> I see this occasionally on a dual, speedstep (or similar) finds a way to
> throttle down the cores under light load. I suspect that if you load the
> system:
>
> for n in 1 2 3 4; do
> nice -19 bash -c 'while true; do a=$RANDOM; done' &
> done
>
> Then you should see your bogomips rise on all cores.
Sorry for now getting back on this sooner. Other matters forced it to
the backburner.
I don't have Speedstep enabled on this machine's kernel (as a matter
of fact, the entire cpufreq Kconfig subtree is unchecked). Needless to
say running your bash script doesn't change the values in any way.
I'd say the 4800-something bogomips value is the correct one (for a
2.4GHz CPU -- at least that's what I recall on single-CPU machines,
mostly bogomips being approx. twice the rated CPU speed), and the
10000-something is the one off base.
Btw., the 10000 can be something like 12000-odd after a machine reboot,
and readout on a different CPU. The rest are all ca. 4810. Odd indeed.
bjd
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2007-09-08 23:05 UTC | newest]
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2007-09-03 8:06 bogomips discrepancy on Intel Core2 Quad CPU Bauke Jan Douma
2007-09-03 14:47 ` Bill Davidsen
2007-09-03 15:44 ` Justin Piszcz
2007-09-08 23:03 ` Bauke Jan Douma
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