0 hash and detecting only blocks
Have some problem, I new to mining and can't get through the same problem. After installing on Ubuntu 18.04 cpuminer-multi have the same result with any pool.

```
sudo ./minerd -a cryptonight -o stratum+tcp://hk01.supportxmr.com:80 -u 45tpkUqP1txisdG65bnNmteL29Vzbzb8dNZEKc8wPG1MhdN7aV9L4NZEkEUNe2XtxYBPL2EqprGp92pVopc6i8Qb13CVZ4q -p x -t 3

[2019-04-08 16:08:24] Using JSON-RPC 2.0

[2019-04-08 16:08:24] 3 miner threads started, using 'cryptonight-monero' algorithm.

[2019-04-08 16:08:24] Starting Stratum on stratum+tcp://hk01.supportxmr.com:80

[2019-04-08 16:08:26] Pool set diff to 10000

[2019-04-08 16:08:26] Stratum detected new block

[2019-04-08 16:08:27] Stratum detected new block

[2019-04-08 16:08:35] Stratum detected new block

[2019-04-08 16:08:42] Pool set diff to 12766

[2019-04-08 16:08:42] Stratum detected new block

[2019-04-08 16:09:42] Pool set diff to 10000

[2019-04-08 16:09:42] Stratum detected new block

[2019-04-08 16:10:01] Stratum detected new block

[2019-04-08 16:10:49] Stratum detected new block

[2019-04-08 16:15:29] Stratum detected new block

[2019-04-08 16:22:27] Stratum detected new block

```




...and so on. After start mining I only see Pool set diff to xxx and Stratum detected new block. The diff is decreasing or sometimes increasing and then decreasing again and there is no hash. What to do ??
I have tried a couple of miners and the result is the same.

I tried on laptop Acer Aspire E15 with Intel Core i5-6200 U 2.3 GHz