On Sun, 23 Jan 2005, Andi Kleen wrote: > Felipe Alfaro Solana <[EMAIL PROTECTED]> writes: > > > > AFAIK, XOR is quite expensive on IA32 when compared to simple MOV > > operatings. Also, since the original patch uses 3 MOVs to perform the > > swapping, and your version uses 3 XOR operations, I don't see any > > gains. > > Both are one cycle latency for register<->register on all x86 cores > I've looked at. What makes you think differently? > > -Andi (who thinks the glibc qsort is vast overkill for kernel purposes > where there are only small data sets and it would be better to use a > simpler one optimized for code size) > How about a shell sort? if the data is mostly sorted shell sort beats qsort lots of times, and since the data sets are often small in-kernel, shell sorts O(n^2) behaviour won't harm it too much, shell sort is also faster if the data is already completely sorted. Shell sort is certainly not the simplest algorithm around, but I think (without having done any tests) that it would probably do pretty well for in-kernel use... Then again, I've known to be wrong :)
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