Thread: 1cpu vs 2cpu
View Single Post
Old 2020-12-31, 16:48   #5
charybdis
 
charybdis's Avatar
 
Apr 2020

26310 Posts
Default

I presume your system has 24 physical cores with hyperthreading.

Setting
Quote:
Originally Posted by cardmaker View Post
NUM_CORES = 12
THREADS_PER_CORE = 2
will run 24 processes for most of the factorization, and unless you force factmsieve.py to only use 12 physical cores, the scheduler will assign one process to each core. The speedup you get from NUM_CORES = 24 relative to NUM_CORES = 12 is only due to the use of hyperthreading, so we shouldn't expect speed to double.

Your factorization with NUM_CORES = 24 had a substantially worse polynomial and still finished quicker than the one with NUM_CORES = 12, so 24 is definitely faster - just nowhere near double the speed.
charybdis is offline   Reply With Quote