Post
Topic
Board Mining (Altcoins)
Re: cpuminer-opt 3.7.6 only using 32 CPUs on a 48 CPU system?
by
joblo
on 15/12/2017, 22:59:25 UTC

Ubuntu 16.04.

When I start cpuminer-opt 3.7.6 on a 48 CPU system, in top/htop I can see only 32 CPUs are used (unexpected).
When I start cpuminer-opt 3.7.3 on a 48 CPU system, in top/htop I can see 48 CPUs are used (expected).

Didn't try other versions.


Command line:

Code:
# ./cpuminer -c config.conf -q
         **********  cpuminer-opt 3.7.6  ***********
     A CPU miner with multi algo support and optimized for CPUs
     with AES_NI and AVX2 and SHA extensions.
     BTC donation address: 12tdvfF7KmAsihBXQXynT6E6th2c2pByTT

CPU: AMD EPYC 7401P 24-Core Processor               .
SW built on Dec 15 2017 with GCC 5.4.0.
CPU features: SSE2 AES AVX AVX2 SHA.
SW features: SSE2 AES AVX AVX2 SHA.
Algo features: AVX AVX2.
Start mining with AVX2.

[2017-12-15 22:06:13] Starting Stratum on stratum+tcp://address:port
[2017-12-15 22:06:13] 48 miner threads started, using 'lyra2z' algorithm.
[2017-12-15 22:06:13] Stratum difficulty set to 10

config.conf:

Code:
{

    "url" : "some-url:port",
    "user" : "some.01234.worker",
    "pass" : "pass",

    "algo" : "lyra2z",
    "api-bind" : 0
}

I presume this is the same system using both versions of cpuminer-opt.

I've reviewed the changes I made for 64 CPU support and they should only have an effect when
there are more than 64 vcores. It's as simple as if num_cpus > 64 do something different else
do as usual.

I can find no reason why it behaves differently or why it maxes at 32.

Test both versions with -D, the debug output may provide a clue.

Edit: Also is there anything unusual about that system? Any virtualization or NUMA?