I've a dual core system (see /proc/cpuinfo at the end) running CentOS 4.4 (fully up-to-date) and I'm running a PHP script that's parsing files and dumping the results into a database. Software versions: # rpm -q php php-4.3.9-3.22 # rpm -q MySQL-server-standard MySQL-server-standard-5.0.27-0.rhel4 # uname -srvmpio Linux 2.6.9-42.0.3.ELsmp #1 SMP Fri Oct 6 06:21:39 CDT 2006 i686 athlon i386 GNU/Linux The thing is, the script process and the MySQL process seem to arbitrarily jump from one CPU to another. That would be fine, I guess, but sometimes both processes are on the same CPU core. Is there a way to keep these processes separate (each one on a different core), or make them "sticky" w.r.t. the CPU cores? # cat /proc/cpuinfo processor : 0 vendor_id : AuthenticAMD cpu family : 15 model : 35 model name : AMD Athlon(tm) 64 X2 Dual Core Processor 4800+ stepping : 2 cpu MHz : 2412.035 cache size : 1024 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 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 ht syscall nx mmxext lm 3dnowext 3dnow pni bogomips : 4825.57 processor : 1 vendor_id : AuthenticAMD cpu family : 15 model : 35 model name : AMD Athlon(tm) 64 X2 Dual Core Processor 4800+ stepping : 2 cpu MHz : 2412.035 cache size : 1024 KB physical id : 0 siblings : 2 core id : 1 cpu cores : 2 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 ht syscall nx mmxext lm 3dnowext 3dnow pni bogomips : 4821.52 -- Florin Andrei http://florin.myip.org/