why the pardiso solver solve the problem Sequential و not parallel ?

my fortran program is solving a linear matrix with 1000*1000 elements with pardiso (comes in attachment.)

the matrix is positive definite (mtype=2)

my questions :

is the solution mode sequential or parallel by default ? if default mode is sequential , can i parallelize that? what?

if not and default mode is parallel ,why the CPU usage is not 100% ?

thanks for taking the time and Apology for  my poor english!!