I have been running the nbench-byte-2.1 benchmark on a mips r4k processor with various combinations of kernel and distribution packages. I initially started with a 2.4.2 kernel using the redhat 5.1 distribution found on the SGI mips site. I compiled nbench native on the target with redhat mounted via nfs. I used this as my base. I then ran a 2.4.6 kernel on the same mips 4k processor, but this time with the redhat 7.0 distribution. I compiled native using the distributions compiler. This resulted in : a 3 % reduction in the Memory Index benchmark a 2 % increase in the Integer Index benchmark a 23 % reduction in the Floating Point Index benchmark Using the same 2.4.6 kernel on the same mips 4k processor, with the redhat 7.1 distribution (compiling native with the distribution's compiler ) I got : a 5.7 % reduction in the Memory Index benchmark a 1.5 % reduction in the Integer Index benchmark a 27 % reduction in the Floating point Index benchmark Also as a test I ran the redhat 5.1 native compiled nbench executable on the 2.4.6 / redhat 7.0 setup and again saw reduced performance : a 4.8 % reduction in the Memory Index benchmark a 1.5 % increase in the Integer Index benchmark a 26 % reduction in the floating point benchmark Although I tried various compiler switches to acheive the highest index I could on a per kernel / per distribution basis ( they weren't always the same ). My basic CFLAGS settings were : CFLAGS = -s -static -Wall -O2 -fomit-frame-pointer -funroll-all-loops -mips2 -finline-functions. >From the above tests it seems that newer does not in fact mean faster. I can only speculate as to why, and so I would appreciate hearing from anyone who : a, has suggestions on how to optimize compiler performance. b, may know why performance seems to degrade with a newer kernel and with a newer distribution ? newer compiler ? c, any other tips for improving kernel / application performance. Wayne __________________________________________________ Do You Yahoo!? Send instant messages & get email alerts with Yahoo! Messenger. http://im.yahoo.com/
