To increase your page speed, you should try your best to avoid or minimize redirects on your website. If a mobile user goes to example.com and it redirects them to www.example.com then redirects them to m.example.com, the user will experience slow page loads. Having a landing page that redirects multiple times to the final landing page will slow your page speed. Instead, you can design your website so that example.com uses a responsive design with different break points for desktops, tablets and mobile devices.