Tuning Threading

PageSpeed uses threads so that resource optimization work does not delay request serving. There are two kinds of threads in use: rewrite threads deal with very short-lived bookkeeping tasks that are generally latency-sensitive, while expensive rewrite threads deal with more computationally expensive tasks that are not in latency-sensitive paths. You can tune the thread count per process if necessary via the NumRewriteThreads and NumExpensiveRewriteThreads options.

Note: IISpeed will autotune the threading settings, for ats_pagespeed manual tuning is required.