Martin Mares <m...@ucw.cz> wrote on 2010/04/23 23:02:29: > > Hello! > > > How did you come to the conclusion the the current code was better than > > the previous version? Seems like "hand waving" to me. > > Did I claim anywhere that the old code is better? I only pointed out
You did when you commited it and I asked twice how you came to that conlusion. Pretty much all recent tests shows otherwise. > the lack of arguments about the new code being better, which is a reason > to stay with the old, tested code. > > > I told told you I had benched the "add carry in C" before and it wasn't > > any better(worse actually). > > Actually, back in the ages when I wrote the old checksum function, I have > checked that it performs better than a trivial implementation, and now you > claim otherwise, so I naturally want to see new data which show that modern > hardware behaves differently. > > > Santiago benched it too and it was better > > or just as good as before. Only the MIPS had a regression. > > If I recall his results correctly, he has performed three tests: > > In the 1st one, your code was 20% faster. > In the 2nd one, it was of the same speed. > In the 3rd one, it was 20% slower. > > Maybe I wear different glasses from yours, but I clearly see that on average, > there is no improvement. You have ignored my tests which also show an improvement. > > > So what now? what more proof do you need? > > First of all, I want at least a rudimentary proof that IT MATTERS AT ALL. > We are spending lots of time talking about a minor (20%) speedup in a small > chunk of code, without having any clue about how often it gets called and what > fraction of the total time is really spent there. 20% is a lot and I not going to bench it any further. if you are not happy with the results so far, nothing I can do will change that.