Dear All, In summary, Vanilla Linux kernel gives average 3-4ms response time. But, when CONFIG_PREEMPT is turned on response is improved dramatically. Less than 100us (microseconds). I love that value. I have tried Three Different Linux kernels. 1. Vanilla 2.6.9x 2. Vanilla + CONFIG_PREEMPT Enabled 3. Vanilla + Preemptible Patch For each case I got following latencies in worst and best situations. 1. Vanilla --------------------------- Best(2000us) Worst(~20000us) 2. CONFIG_PREEMPT ------- Best(75us) Worst(700us) Actually all of above test were carried out using in-house small test program. Test program has two components and Server wakes up when client send some data. We are measuring Round Trip Time from client to server.Above values are in us = microsecond. Actually, change of HZ value makes kernel unstable. I saw there are kernel code segments which assumes HZ value is either 1000, 250 or 512?? . However increase of HZ made kernel more responsive. I am going to use 1000 HZ and CONFIG_PREEMPT for while. In next few days I will try to carry out some more performance test with Preemptible Patch and RT Linux. Let you know the results of This Great Kernel. Like to thank all of your help and kind response to my mails. -- Tharindu Rukshan Bamunuarachchi all fabrications are subject to decay -- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
