There are two kernel parameters that control the performance of the namei cache:
hit %value shown by sar -n is consistently low (for example, less than 65%), increase CACHEENTS until
hit %increases to a satisfactorily high value (for example, more than 90%). Poor name-lookup performance can result if the value of CACHEENTS is less than twice the grown size of the in-core inode table. As a rough guide, CACHEENTS should be approximately three times the grown size of the in-core inode table reported by the
inod-szfield of sar -v.
The value of HASHQS should be at least one third the value of CACHEENTS. For example, if the value of CACHEENTS is 1000, a suitable value for HASHQS would be 334.
Remember that each time you change the value of a kernel parameter,
you must relink the kernel
and reboot your system for the new value to take effect.
``Configuring kernel parameters''
for details of how to change the values of kernel parameters.