On Fri, 19 Dec 2003, Mike Tancsa wrote: > > We are replacing a box that is fairly busy with many different processes > (sendmail / pop3). The new MB and CPU is hyperthreading capable. Is it > worth it to enable this ? Does anyone have any real world experiences with > it in RELENG_4 that say one way or the other to use or not use it ? > > dmesg shows, > > CPU: Intel(R) Pentium(R) 4 CPU 3.00GHz (2992.52-MHz 686-class CPU) > Origin = "GenuineIntel" Id = 0xf29 Stepping = 9 > > 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,S > SE2,SS,HTT,TM,PBE> > Hyperthreading: 2 logical CPUs > > ---Mike
HyperThreading usually requires special smarts in the OS process scheduler so that the cores don't bottleneck each other with cache thrashing and pipeline stalls/starvation. Without this, Hyperthreading is usually slightly slower than non-Hyperthreading. 4.x does not have a scheduler that understand HTT, but 5.2-CURRENT does. Scott _______________________________________________ [EMAIL PROTECTED] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-stable To unsubscribe, send any mail to "[EMAIL PROTECTED]"
