Multi-Threading resample seems not working for continuous process.

[Vccxx]

I have installed both gslrandom and enabled OpenPM support on my ubuntu 18.04 machine . But when I run resample using these code:

    def genHawkesModel(dates,ids):
        K = len(np.unique(ids))
        network_hypers = {"p":0.25,"allow_self_connections":False}
        model = ContinuousTimeNetworkHawkesModel(
                    K,
                    dt_max = 1,
                    network_hypers=network_hypers,
                )
        model.add_data(dates,ids,T=dates.max() + 1)
        return model

    hawkes_model = genHawkesModel(dates,ids)
    N_samples = len(np.unique(ids))
    hawkes_lls = [hawkes_model.log_likelihood()]
    logging.info("Start iterating")
    for itr in progprint_xrange(N_samples, perline=25):
        hawkes_model.resample_model()
        hawkes_lls.append(hawkes_model.log_likelihood())

I found this code is running too slow :

I check the cpu usage using top command, finding that the program only using one cpu when resampling:

I'm sure I have install gslrandom on my machine (both pip and apt):

I want to know how to make sure the resample process is running in the multi-threading mode so that I can do the resample as fast as possible.
Thank you and looking forward for your reply.