Lets use a simple software to warm pages so they load faster and already in cache.
Before we do anything we need to install the following software
sudo apt-get install libxml-xpath-perl siege -y
Now lets setup Sitemap in Magento prior doing anything  – assuming that’s all taken care follow the following steps.
cat /home/yoursite/public_html/sitemap.xml | xpath -q -e "/urlset/url/loc/text()" > /root/tmp.urls
If the file is not local simply run the following
curl --silent http://example.com/sitemap.xml | xpath -q -e "/urlset/url/loc/text()" > tmp.urls
Now let’s make it warm
siege -v -c 1 -r `cat tmp.urls | wc -l` -f /root/tmp.urls
That’s it.