Dogecoin notes

I toyed around with running Dogecoin on my iMac. Some notes.

Wallet

  • The official Dogecoin client starts by downloading the blockchain. That is still very big, gigabytes I think. I didn’t wait for it to finish. Apparently the initial sync can be made faster by download a file separately. Derp. Or use an alternate client that doesn’t require the whole blockchain: maybe MultiBit maybe something from @datamingle.
  • Crashplan will try to back up the Dogecoin state, including gigabytes of blockchain data. Have to exclude both the “blocks” and “chainstate” directories; but then don’t exclude wallet.dat from the backup! That’d be dumb. (Or do: is it encrypted adequately in the backup?)

Mining. Er, digging.

  • The mining pool I picked is fast-coin. It’s the biggest no-fee pool right now.
  • I tried several miners. fast-pool recommends cgminer, which is an awkward command line program and lacks the –scrypt flag they try. cgminer recommends Asteroid, which hung for 1+ minutes with no UI feedback. I finally settled on MacMiner 1.5.18e. It’s basically a GUI wrapper for command line tools, including bfgminer.
  • The CPU miner seems to work well. Each CPU (i7 at 3.4GHz) is giving me about 5.7 khash/second. I have 8 CPUs, so I’m doing about 45 khash/second.
  • The pool as a whole is doing 8.2G Hash/sec with 5891 worker, or an average of 1400 khash/second for a worker. So my worker is about 3% of the average worker. I’m not sure, but I suspect “worker” means “single computer” in the pool, so this is a fair comparison.
  • My Mac is using about 140W running the CPU miner, or about $1 / day at PG&Es outrageously high price for electricity. Temperature isn’t so bad, the fans aren’t making noise.
  • According to this litecoin site my AMD 6970M GPU should get about 210khash / second. That’s about 5x what my CPUs can do; a significant improvement, but not ridiculously so.
  • According to that list very few GPUs push 1000 khash/second. I wonder how the pool average is 1400? Surely no one is building Dogecoin mining rigs.
  • The MacMiner GPU client crashes on my iMac soon after starting to run. There are some flags to tune the GPU usage settings but I have them all set to defaults. It may simply not work, who knows. (it’s an EXC_BAD_ACCESS, KERN_INVALID_ADDRESS, on the main thread).
  • In MacMiner I tried using these command line flags I found on the 6970M stats page and it still crashes.
    -I 13 -g 1 -w 128 –thread-concurrency 5600
  • When the MacMiner GPU client crashes, the whole applications crashes but it manages to leave behind a running bfgminer process that is consuming resources somehow. I had about 4 hanging around before I figured out why my Mac was so slow even though I’d shut off all the doges.
  • I was able to run the MacMiner’s version of bgfminer by hand from the command line. It appears to work, yields about 150khash/second.
    bfgminer -S opencl:auto -o stratum.fast-pool.com:3002 -u workername -p password
    Update:
     see below for the –scrypt flag
  • The GPU miner costs about 100W to run, or about $0.33 cents a day.
  • There’s contention between the GPU and CPU client. No CPU client: 160 khash/sec. With all 8 CPUs pegged: 100 kh/s. Those 8 CPUs are only generating 45 kh/s, so it’s better to run GPU only.
  • Nothing seems to check the worker password I set on bfgminer. The username is checked though.

It may be that GPU miner does not work. bfgminer with just the GPU running never got me any credit in my pool. And the displayed hash/sec values don’t really make sense, or rather the units don’t. The display literally reads “150 MH/s”, which I was interpreting as a sane kH/s.

The fact bfgminer is not checking passwords also makes me suspicious. Maybe it’s just not posting work credit correctly. Update: yeah, bfgminer is not getting my credit with the pool and is reporting weird hash/sec speeds. Something is just wrong. Turns out I wasn’t setting the –scrypt flag; see below.

Profit

  • The pool tells me a rate of 21 khash/sec is worth 74 doge/day.
  • If my best rate is 150 khash/sec, that would be about 530 doge/day.
  • At a rate of 1000 Doge = $1.17, I could make $0.62 / day mining Dogecoin at a cost of $0.33 in electricity.

bfgminer screenshot

No idea what this really means. Like I said, this miner isn’t getting me credit in the pool.

Screen Shot 2014-02-27 at 11.32.55 AM

Update: scrypt

Oops, I was running bfgminer without the “–scrypt” flag. That will still take work and appear to do it, but with the old Bitcoin algorithm and not the new litecoin/dogecoin scrypt algorithm. And nothing ever gets posted. The following command line actually works and posted work to the pool:

bfgminer –scrypt -S auto -o stratum.fast-pool.com:3002 -u worker -p password

With no -I flag (“intensity”, a nice value) I get the desktop default, which yields about 12 kh/s from the GPU and another 12 kh/s from the 8 CPUs together. Ie: much slower than the CPU only miner I was using before. Switching to GPU-only mining doesn’t help. The results seem fairly random .With -I 12 (commonly recommended) I get about 55 kh/s; maybe 60 kh/s if I turn off the CPU miner. “-I 8” is slow again, 8 kh/s. “-I -10” locks up the machine solid, even a remote ssh login and killing the process didn’t recover. “-I 20” also locked up the GUI, maybe that was just bad luck?

Running GPU only results never report to the pool. Maybe the computations aren’t correct.

BTW, all this testing is hard to do because it seems the way the pool works it takes a few minutes before any work shows up. And if your rate is too slow it may never show up, maybe you’re always posting too late?