How to measure the time HTTP requests spend sitting in the accept-queue?
- by David Jones
I am using Apache2 on Ubuntu 9.10, and I am trying to tune my configuration for a web application to reduce latency of responses to HTTP requests.
During a moderately heavy load on my small server, there are 24 apache2 processes handling requests. Additional requests get queued.
Using "netstat", I see 24 connections are ESTABLISHED and 125 connections are TIME_WAIT.
I am trying to figure out if that is considered a reasonable backlog.
Most requests get serviced in a fraction of a second, so I am assuming requests move through the accept-queue fairly quickly, probably within 1 or 2 seconds, but I would like to be more certain.
Can anyone recommend an easy way to measure the time an HTTP request sits in the accept-queue?
The suggestions I have come across so far seem to start the clock after the apache2 worker accepts the connection. I'm trying to quantify the accept-queue delay before that.
thanks in advance,
David Jones
