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