1 files changed, 33 insertions, 4 deletions

diff --git a/src/net.cpp b/src/net.cpp
index e08f6f7..34c608c 100644
--- a/src/net.cpp
+++ b/src/net.cpp
@@ -1801,7 +1801,21 @@ void ThreadBitcoinMiner(void* parg)
 // Start the miners. Returns how many actually got off the ground.
 int StartMinerThreads()
 {
-    int nThreads = MinerThreadCount();
+    // MinerThreadCount() sizes the SOLO miner, where each thread hashes a
+    // template of its own and more threads is simply more hashrate.
+    //
+    // Participant mode is not that shape. Every thread that enters
+    // BitcoinMiner() takes the MINE_PARTICIPANT branch, and that branch is a
+    // whole miner: its own Stratum session to the pool, its own payout address
+    // from the rotation, and its own pool of /hashthreads worker threads. So
+    // the two counts multiply instead of dividing, and the machine ends up
+    // running MinerThreadCount() x nHashThreads hashing threads plus one pool
+    // connection each. On a 12-core host with /hashthreads=2 that is 11
+    // sessions and 22 hash threads -- roughly 2x the cores, which is not more
+    // work done, only more contention -- and with /hashthreads unset it is 11
+    // sessions of 11 workers. One session is the entirety of participant mode;
+    // /hashthreads is what sizes it, and it can then mean what it says.
+    int nThreads = (nMineMode == MINE_PARTICIPANT) ? 1 : MinerThreadCount();
     int nStarted = 0;
     for (int i = 0; i < nThreads; i++)
     {
@@ -1813,9 +1827,24 @@ int StartMinerThreads()
     // The dataset is one allocation shared by all of them; only the 2 MB
     // scratchpads multiply. Printed because "why is it using 2 GB" is the first
     // question anyone asks.
-    printf("Mining with %d thread(s) of %u core(s) -- about %d MB "
-           "(~2080 MB shared RandomX dataset + ~2 MB per thread)\n",
-           nStarted, AvailableCoreCount(), 2080 + 2 * nStarted);
+    //
+    // Participant mode reports the workers that session will run, not the one
+    // thread that runs it: the hash thread count is the number an operator
+    // watches, and it is the number that was wrong here. It is otherwise only
+    // logged under -debug, which is how 11 sessions ran unnoticed.
+    if (nMineMode == MINE_PARTICIPANT)
+    {
+        int nWorkers = ParticipantHashThreadCount();
+        printf("Mining for the pool with %d hash thread(s) of %u core(s) -- about %d MB "
+               "(~2080 MB shared RandomX dataset + ~2 MB per thread)\n",
+               nWorkers, AvailableCoreCount(), 2080 + 2 * nWorkers);
+    }
+    else
+    {
+        printf("Mining with %d thread(s) of %u core(s) -- about %d MB "
+               "(~2080 MB shared RandomX dataset + ~2 MB per thread)\n",
+               nStarted, AvailableCoreCount(), 2080 + 2 * nStarted);
+    }
     return nStarted;
 }