Dashboard load times with gethostbyaddr()

Hey there,

I use Dashboard Widgets Suite on a number of WordPress sites and have used it for years (thanks!!), primarily for the System Info, Control Panel, Error Log, and Debug Log widgets.

I’ve been tracking down a very slow WordPress dashboard issue (14–20 second load times) and eventually narrowed it down to the System Info widget.

Using our PHP-FPM slow log, every slow request pointed to the same call stack:

gethostbyaddr()
dashboard_widgets_suite_get_host_name()
dashboard_widgets_suite_get_client_infos()
dashboard_widgets_suite_system_info()
wp_dashboard()

Specifically, this function:

function dashboard_widgets_suite_get_host_name() {
return isset($_SERVER['REMOTE_ADDR'])
? sanitize_text_field(gethostbyaddr($_SERVER['REMOTE_ADDR']))
: 'n/a';
}

The reverse DNS lookup performed by gethostbyaddr() appears to block page generation while waiting for the lookup to complete.

Couple things I noticed:

• The issue occurs on multiple servers.
• It also occurs on sites that are both behind and not behind Cloudflare.
• CPU, MySQL, Redis, and disk I/O were all normal.
• As soon as I bypassed only the gethostbyaddr() call, the WordPress dashboard became nearly instantaneous (around 1–2 seconds instead of 14–20 seconds).

Not sure why this is happening but I thought I’d report it.

Thanks!