Linux audit performance impact

Hi Steve, I am Logeswari working for HP. We want to know audit performance impact on RHEL and Suse linux to help us evaluate linux audit as data source for our host based IDS. When we ran our own performance test with a test audispd plugin, we found if a system can perform 200000 open/close system calls per second without auditing, system can perform only 3000 open/close system calls auditing is enabled for open/close system call which is a HUGE impact on the system performance. It would be great if anyone can help us answering the following questions. 1) Is this performance impact expected? If yes, what is the reason behind it and can we fix it? 2) Have anyone done any benchmarking for performance impact? If yes, can you please share the numbers and also the steps/programs used the run the same. 3) Help us validating the performance test we have done in our test setup using the steps mentioned along with the results attached. Attached test program (loader.c) to invoke open and close system calls. Attached idskerndsp is the audispd plugin program. We used time command to determine how much time the system took to complete 50000 open/close system calls without (results attached Without-auditing) and with auditing enabled on the system (With-auditing-NOLOG-audispd-plugin and With-auditing-RAW) System details: 1 CPU machine OS Version RHEL 6.5 Kernel Version uname -r 2.6.32-431.el6.x86_64 Note: auditd was occupying 35% of CPU and was sleeping for most of the time whereas kauditd was occupying 20% of the CPU. Thanks & Regards, Logeswari.