On Mon, Jun 11, 2007 at 05:38:55PM +0200, Ingo Molnar wrote:

* Paul E. McKenney [off-list ref] wrote:

quoted

quoted

hm, what affinity do they start out with? Could they all be pinned 
to CPU#0 by default?

They start off with affinity masks of 0xf on a 4-CPU system.  I would 
expect them to load-balance across the four CPUs, but they stay all on 
the same CPU until long after I lose patience (many minutes).

ugh. Would be nice to figure out why this happens. I enabled rcutorture 
on a dual-core CPU and all the threads are spread evenly.

Here is the /proc/cpuinfo in case this helps.  I am starting up a test
on a dual-core CPU to see if that works better.

							Thanx, Paul

processor       : 0
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 5
model name      : AMD Opteron(tm) Processor 844
stepping        : 8
cpu MHz         : 1793.105
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall mmxext lm 3dnowext 3dnow
bogomips        : 3522.56

processor       : 1
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 5
model name      : AMD Opteron(tm) Processor 844
stepping        : 8
cpu MHz         : 1793.105
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall mmxext lm 3dnowext 3dnow
bogomips        : 3579.90

processor       : 2
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 5
model name      : AMD Opteron(tm) Processor 844
stepping        : 8
cpu MHz         : 1793.105
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall mmxext lm 3dnowext 3dnow
bogomips        : 3579.90

processor       : 3
vendor_id       : AuthenticAMD
cpu family      : 15
model           : 5
model name      : AMD Opteron(tm) Processor 844
stepping        : 8
cpu MHz         : 1793.105
cache size      : 1024 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 1
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall mmxext lm 3dnowext 3dnow
bogomips        : 3579.90