[Haskell-cafe] GHC's parallel garbage collector -- what am I doing wrong?

[Daniel Fischer]

Am Montag 01 März 2010 18:52:53 schrieb Michael Lesniak:
> Hello Daniel,
>
> > Sorry, can't reproduce it:
>
> That's also very helpful, so thanks for this :-)
>
> > Seems your system has a problem synchronising the cores for GC.
>
> Correct. Could you please tell me your system configuration (i.e. GHC
> compiler and OS?)

ghc-6.12.1 (btw, I also tried with 6.10.3, there -N2 [and even -N3] are 
really close to -N1,
-N1: 7.57user 0.01system 0:07.58elapsed 100%CPU (+/- 0.02s)
-N2: 7.59user 0.03system 0:07.61elapsed 100%CPU (+/- 0.02s)
-N3: 7.60user 0.03system 0:07.62elapsed 100%CPU - 8.12user 0.00system 
0:07.87elapsed 103%CPU
typical -N3 behaviour with 6.12.1: 14.43user 0.03system 0:11.05elapsed 
130%CPU
),
openSuSE 11.1,

$ uname -a
Linux linux-mkk1 2.6.27.42-0.1-pae #1 SMP 2010-01-06 16:07:25 +0100 i686 
i686 i386 GNU/Linux

$ cat /proc/cpuinfo 
processor       : 0                             
vendor_id       : GenuineIntel                  
cpu family      : 15                            
model           : 4                             
model name      : Intel(R) Pentium(R) 4 CPU 3.06GHz
stepping        : 9                                
cpu MHz         : 3058.856                         
cache size      : 1024 KB                          
physical id     : 0                                
siblings        : 2                                
core id         : 0                                
cpu cores       : 1                                
apicid          : 0                                
initial apicid  : 0                                
fdiv_bug        : no                               
hlt_bug         : no                               
f00f_bug        : no                               
coma_bug        : no                               
fpu             : yes                              
fpu_exception   : yes                              
cpuid level     : 5                                
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 lm 
constant_tsc pebs bts pni monitor ds_cpl tm2 cid cx16 xtpr lahf_lm
bogomips        : 6117.71
clflush size    : 64
power management:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 15
model           : 4
model name      : Intel(R) Pentium(R) 4 CPU 3.06GHz
stepping        : 9
cpu MHz         : 3058.856
cache size      : 1024 KB
physical id     : 0
siblings        : 2
core id         : 0
cpu cores       : 1
apicid          : 1
initial apicid  : 1
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
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 lm 
constant_tsc pebs bts pni monitor ds_cpl tm2 cid cx16 xtpr lahf_lm
bogomips        : 6118.12
clflush size    : 64
power management:


>
>
> Cheers,
>  Michael