Custom nonce trying strategy

[Mouradif]

I was thinking, when trying out nonces, if everyone starts with 0 and increments, then the faster computer will ALWAYS get a valid nonce before all the others. So I wanted to change that nonce trying strategy on the version I'm running, thinking maybe I can find a working nonce that other nodes wouldn't try until late.

I've been trying to read through cpu-miner.c but without much success. If I wanted for example to start from the max value and decrement the nonce for each try how would I do that?

[Mouradif]

Here's what I tried, I have the feeling something is off because I don't see the process using all the CPU like it used to:

diff --git a/cpu-miner.c b/cpu-miner.c
index ef2fc76..d14af92 100644
--- a/cpu-miner.c
+++ b/cpu-miner.c
@@ -1193,9 +1193,9 @@ static void *miner_thread(void *userdata)
                if (memcmp(work.data, g_work.data, 76)) {
                        work_free(&work);
                        work_copy(&work, &g_work);
-                       work.data[19] = 0xffffffffU / opt_n_threads * thr_id;
+                       work.data[19] = 0xffffffffU / opt_n_threads * (thr_id + 1);
                } else
-                       work.data[19]++;
+                       work.data[19]--;
                pthread_mutex_unlock(&g_work_lock);
                work_restart[thr_id].restart = 0;

[pooler]

I was thinking, when trying out nonces, if everyone starts with 0 and increments, then the faster computer will ALWAYS get a valid nonce before all the others.

No, you've fallen into a common fallacy. Mining servers provide each client with unique work, so there is no direct competition among miners.

[Mouradif]

When you say mining servers you mean pools ? What if I'm solo mining ?

[pooler]

When you say mining servers you mean pools ? What if I'm solo mining ?

I mean any kind of server the miner gets its work from. To mine solo you probably told cpuminer to connect to a local coin daemon; that would be your mining server.

[Mouradif]

Understood! Thanks!

I got thrown off by this answer of yours : #183 (comment)

This may not be the right place but if you would kindly explain the difference that would help a lot

[pooler]

The nonce is not the only thing that can be changed in a block header to make it different. In particular, servers make sure that each miner works on a different Merkle root hash.