Hi, I know that the MySQL runs on a single process (can see with command: ps aux). I know that the MySQL is multithreaded and if I run in an SMP kernel, the load will be balance smoothly by the processors. I have one server running only MySQL, is a Quad Core Intel(R) Xeon(R) CPU E5430 2.66GHz # uname -a Linux one.forums-free.com 2.6.18-6-686 #1 SMP Tue Jun 17 21:31:27 UTC 2008 i686 GNU/Linux But if I run the command "mpstat", I see that the load is not equal in all processors. # !mpstat -P ALL 60 01:44:56 CPU %user %nice %sys %iowait %irq %soft %steal %idle intr/s 01:45:56 all 15,02 0,00 2,04 17,17 0,08 0,66 0,00 65,03 2879,96 01:45:56 0 23,11 0,00 2,02 44,54 0,05 0,72 0,00 29,57 791,20 01:45:56 1 18,91 0,00 4,10 13,11 0,28 1,68 0,00 61,88 2088,74 01:45:56 2 8,83 0,00 1,08 4,87 0,00 0,13 0,00 85,05 0,00 01:45:56 3 9,23 0,00 0,93 6,16 0,00 0,13 0,00 83,54 0,00 Even under high load, the last processor still have a high IDLE. CPU0 sometime have 0% IDLE and the last processor is in 60-70% idle. Any idea how to use all power from all processors? Thanks.
Edit your my.cnf and change/add 'thread_concurrency' to 8 in the [mysqld] section and restart mysqld You have some pretty high iowait btw, that will drive up the load avg.
This option (thread_concurrency) is only to Solaris systems. The don't have any impact on Linux. (I use the lasted Debian x64) http://dev.mysql.com/doc/refman/5.0/en/server-system-variables.html#option_mysqld_thread_concurrency Any other idea?