As long promised I finally did find some time to work a bit more on my RandomX support (the things one does over Thanksgiving “holidays” – sigh)… and at least experimentally, uploaded a first version with randomx support (use “–algo rx”). As usual, downloads are on http://www.lukminer.net/releases/ .
To indicate that this is the first version that supports anything other than cryptonight variants I went all out and tagged this one as “2.0.0” (which yes, means that I completely skipped all 1.x version numbers – well, let’s not go into that). Note I added rx support only for phis – almost all my users are only interested in that, anyway, and for regular CPUs there’s plenty other miners out there that support it, too…. so.
In terms of performance: On my 68-core Phi 7250 I’m getting ca 6800 hasher per second. That’s “decent” if you compare it to what the benchmark pages report for mid-range Xeons, and pretty good compared to GPUs … but quite a bit lower than what a high-end Epyc will do. For those that are wondering: RandomX (at least in my current implementations) stresses mostly scalar performance, and thus benefits from high clock rates and multi-issue out-of-order … none of which the Phi was designed for: Yes, it does have 4-way hyperthreading (which helps), and some sort of out-of-order processing – but it runs at only 1.4GHz (3x lower than an Epyc!), and only has a single scalar pipe (it has one more pipe for vector instructions, but there aren’t many). For CryptoNight the MCDRAM was the big saviour (CN is mostly memory-bound) – but on RandomX, the phi is actually CPU bound, not memory bound, so the MCDRAM doesn’t help that much.
Anyway – we’ll have to see if ~7kH/s is economically feasible …. guess we’ll know in a few days how price and difficulty will pan out. I also have a few more ideas on optimizations … well, we’ll see.
’til then – happy mining!