Improving SMP performance?

[John]

On Tue, Apr 27, 2010 at 05:32:58PM -0700, Neil Short wrote:
> I'm somewhat disappointed in the performance in my laptop which is supposed to have a really fast processor. Is there some way to get more out of the processor?
> 
> 
> [neshort/] uname -a
> FreeBSD carmen 8.0-STABLE FreeBSD 8.0-STABLE #1: Thu Apr 15 19:54:24 MST 2010     neshort at carmen:/usr/obj/usr/src/sys/CARMEN  i386
> [neshort/] dmesg
> ...
> Timecounter "i8254" frequency 1193182 Hz quality 0
> CPU: Intel(R) Core(TM) i3 CPU       M 330  @ 2.13GHz (2127.92-MHz 686-class CPU)
>   Origin = "GenuineIntel"  Id = 0x20652  Family = 6  Model = 25  Stepping = 2
>   Features=0xbfebfbff<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,HTT,TM,PBE>
>   Features2=0x98e3bd<SSE3,DTES64,MON,DS_CPL,VMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,SSE4.1,SSE4.2,POPCNT>
>   AMD Features=0x28000000<RDTSCP,LM>
>   AMD Features2=0x1<LAHF>
>   TSC: P-state invariant
> real memory  = 4294967296 (4096 MB)
> avail memory = 3066707968 (2924 MB)
> ACPI APIC Table: <HPQOEM SLIC-MPC>
> FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
> FreeBSD/SMP: 1 package(s) x 2 core(s) x 2 SMT threads
>  cpu0 (BSP): APIC ID:  0
>  cpu1 (AP): APIC ID:  1
>  cpu2 (AP): APIC ID:  4
>  cpu3 (AP): APIC ID:  5
> 
> 
> ======
> 
>  "What did you do?" the man holding the flashlight asked.
> 
>  "I put down a spider," he said, wondering why the man didn't see; in the beam of yellow light the spider bloated up larger than life. "So it could get away."
> 

In what way are you disappointed?  It may be SMP, but for any single
thread, it cannot go faster than one of the processors.  If you are
measuring a single-threaded task, that's all you can get.  Or could
it be that IO is limiting your performance?  Without knowing what
it is you want to do, and what you are experiencing, it is very hard
to know how to help you.  If you are just looking at the clock speed,
please understand that CPU manufacturers lately are working to LOWER
clocks speeds because it saves power, and to speed up the processors
by using wider microinstructions and more sophisticated pipelining
techniques to gain speed without just wiggling things at a higher
frequency.
-- 

John Lind
john at starfire.MN.ORG