Thanks for your code. It's nice to see people get rewarded for their efforts (though it doesn't always happen). Well, I've tried it on my own miner (minerd) and have some very strange findings.
https://forum.bitcoin.org/index.php?topic=21275.0
First of all, minerd supports up to 4 vectors, and when I add this change to my kernel, it actually _slows down_ the 4 vector version. But when I override it to set 2 vectors, it speeds it up. However, once it's sped up, I then get runs of rejected shares. I tried it multiple times with and without and it does appear to be just this change that causes it, so I'm not sure what's going on.
https://forum.bitcoin.org/index.php?topic=21275.0
First of all, minerd supports up to 4 vectors, and when I add this change to my kernel, it actually _slows down_ the 4 vector version. But when I override it to set 2 vectors, it speeds it up. However, once it's sped up, I then get runs of rejected shares. I tried it multiple times with and without and it does appear to be just this change that causes it, so I'm not sure what's going on.
I honestly do not know what's up with that, I saw ATI asm yesterday for the first time and can't tell you exactly what's wrong yet. All I know is that the truth tables match for the Ma() function with and without my modifications. Yet, here's a couple of ideas -
1 glancing through the doc, radeons are VLIW5 = 4+1, with 4 'normal' pipelines and one transcendental pipe, which can do a restricted set of instructions. I don't know where BFI_INT gets executed, but if it is only in the trans. pipe, then doing too many BFI's can hurt the performance by making that pipe a bottleneck. Check the docs and let us know, if you don't mind.
2 if (z^x) isn't already used in other places in your code, then it may be pushing up the register usage and you're running less threads in parallel. Again, I don't know much about ATI, but it would be the first thing I'd check if we were on nVidia/CUDA.
3 something else altogether...
Not sure. Sorry. If I think of anything else, I'll post it
In the meantime, it would also suck if people started getting more rejected shares... hmmm. I don't, it does work for me, but I encourage everyone to check their results (the actual amount of accepted shares that they get).
), so could the same be happening to you?