Working with Streaming Data example does'n show up any graph

Hi all,

I’m new to holoviews and hope I did’nt oversaw a similiar post to this topic.

I’m using holoviews version 1.14.8 with python 3.9 from recent anaconda distribution and are trying to run the galery examples which works fine in principle.

Unfortunataley I can’t get the psutils example to work:

Streaming Psutil — HoloViews v1.14.8

It runs without throwing an error message but there’s no graph coming up, not even an empty one

Output in jupyter notebook looks like this:

What goes wrong ?
Thanks in advance.

I suspect that this example is pretty old, which is why it does not work anymore. Luckily I could get it to work by updating the example to the following:

import datetime as dt

import psutil
import pandas as pd
import holoviews as hv
import panel as pn
from holoviews import dim, opts


# Define functions to get memory and CPU usage
def get_mem_data():
    vmem = psutil.virtual_memory()
    df = pd.DataFrame(dict(,
    return df*100

def get_cpu_data():
    cpu_percent = psutil.cpu_percent(percpu=True)
    df = pd.DataFrame(list(enumerate(cpu_percent)),
                      columns=['CPU', 'Utilization'])
    df['time'] =
    return df

# Define DynamicMap callbacks returning Elements
def mem_stack(data):
    data = pd.melt(data, 'index', var_name='Type', value_name='Usage')
    areas = hv.Dataset(data).to(hv.Area, 'index', 'Usage')
    return hv.Area.stack(areas.overlay()).relabel('Memory')

def cpu_box(data):
    return hv.BoxWhisker(data, 'CPU', 'Utilization', label='CPU Usage')

# Set up StreamingDataFrame and add async callback
cpu_stream = hv.streams.Buffer(get_cpu_data(), 800, index=False)
mem_stream = hv.streams.Buffer(get_mem_data())

def cb():

# Define DynamicMaps and display plot
cpu_dmap = hv.DynamicMap(cpu_box, streams=[cpu_stream])
mem_dmap = hv.DynamicMap(mem_stack, streams=[mem_stream])

plot = (cpu_dmap + mem_dmap).opts(
    opts.Area(height=400, width=400, ylim=(0, 100), framewise=True),
    opts.BoxWhisker(box_fill_color=dim('CPU').str(), cmap='Category20',
                    width=500, height=400, ylim=(0, 100))

callback =, period=500)


1 Like

yes ist works for me as well !

Thanks very much !