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Is it normal for ethminer to find a solution to a problem, and even after submitting it upstream, it still continues to hash the same problem?

Here is an example: (Genoil's ethminer in stratum mode)

m 12:22:43|ethminer Mining on PoWhash #c936d2df : 0.00MH/s [A37+0:R0+0:F0] ℹ 12:22:44|openclminer0 Solution found; Submitting to stratum-server ... ℹ 12:22:44|openclminer0 Nonce: 0x501061248666b5d5 ℹ 12:22:44|stratum B-) Submitted and accepted. m 12:22:44|ethminer Mining on PoWhash #c936d2df : 29.36MH/s [A38+0:R0+0:F0] m 12:22:45|ethminer Mining on PoWhash #c936d2df : 37.75MH/s [A38+0:R0+0:F0] m 12:22:46|ethminer Mining on PoWhash #c936d2df : 37.75MH/s [A38+0:R0+0:F0] m 12:22:47|ethminer Mining on PoWhash #c936d2df : 33.55MH/s [A38+0:R0+0:F0] m 12:22:48|ethminer Mining on PoWhash #c936d2df : 41.94MH/s [A38+0:R0+0:F0] m 12:22:49|ethminer Mining on PoWhash #c936d2df : 33.55MH/s [A38+0:R0+0:F0] m 12:22:50|ethminer Mining on PoWhash #c936d2df : 41.94MH/s [A38+0:R0+0:F0] m 12:22:51|ethminer Mining on PoWhash #c936d2df : 33.55MH/s [A38+0:R0+0:F0] m 12:22:52|ethminer Mining on PoWhash #c936d2df : 41.94MH/s [A38+0:R0+0:F0] m 12:22:53|ethminer Mining on PoWhash #c936d2df : 33.55MH/s [A38+0:R0+0:F0]

Notice that even after the solution is submitted and accepted upstream, the miner continues to mine the same PoWhash #c936d2df for which it found a solution.

I inspected the network traffic and found that the problem (if there is one) is the upstream stratum pool, which accepts the request and then takes a very long time to give me another job to work on.

So the question - is the mining pool bugged? Shouldn't it be giving me new work immediately after I find a solution?

Or is it expected that there may be multiple solutions to the same problem, and it's OK for ethminer to keep crunching numbers after finding a solution?

EDIT: This has been observed while using multiple upstream stratum pools.

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The PowHash is the target block header hash. If you find it, you just solved a block.

A solution found, however, is not a new block but simply a share submitted to a mining pool. Thus, the PowHash you are working on does not change after submitting a share to the pool, but only if you are finding a block accepted by the network.

| improve this answer | |
  • When I'm connected to eth-proxy I notice that it always sends me a new PoWhash to work on immediately when I submit a solution to it. However connecting directly to a stratum server does not do this. Is that some feature built in to eth-proxy, and if so then why wouldn't stratum servers want to send a new PoWhash immediately after accepting a found solution? – Ross Perkins Jul 19 '16 at 19:47

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