To enhance perfomance, I'd recommend you to enable large page on your OS (root account is required). A) Linux x86 32bit ... (number of core) * 4 pages x86 64bit ... (number of core) * 8 pages POWER 32/64bit ... (number of core) * 1 pages If you want to allocate 64 large pages, $shell> echo 0 > /proc/sys/vm/nr_hugepages # need to be reset $shell> echo 65 > /proc/sys/vm/nr_hugepages # add 1 extra page $shell> echo 3355443200 > /proc/sys/kernel/shmmax # just large number $shell> echo 3355443200 > /proc/sys/kernel/shmall Also may add a few lines into /etc/security/limits.conf file. * hard memlock unlimited * soft memlock unlimited Then restart sshd (/etc/init.d/sshd restart). B) Solaris You don't have to set up. C) Windows (Windows Server 2003 or later, XP 64bit) You have to assign memory lock operation to your account. Control Panel -> Administrative Tools -> Local Security Policy -> Local Policies -> User Rights Assignment -> Lock pages in memory D) AIX Ask your administrator E) Tru64 UNIX Assign shared memory at boot time. F) Other aarchitecture which doesn't have Large TLB enhancement If you have root permission, please install device driver which located in drivers/mapper. $shell> cd drivers/mapper $shell> make $shell> insmod mapper.ko $shell> ./device_setup Then enable DEVICEDRIVER_ALLOCATION = 1 in Makefile.rule.