most of value of $request_time is 0.000

[Maxim Dounin]

Hello!

On Wed, Mar 25, 2015 at 11:55:14AM +0800, baipeng wrote:

> Our version of nginx is nginx/1.0.8 and we have write a third 
> party module to handle the http request. Because the process 
> model of our third party module is synchronous so the nginx 
> worker process will be blocked until one request  accomplished.
> The average time cost of one request is about 50ms.But After we 
> set $request_time in nginx.conf, the most of the value of 
> $request_time is 0.000.Even we set timer_resolution 1ms in 
> nginx.conf most of value of $request_time is still 0.000.
> Are there anyone can tell me why it occured?

Time as seen by nginx is only updated once per event loop 
iteration, so if you block processing for a while and then 
finalize the request - this time won't be visible in 
$request_time.

The timer_resolution may change things on some platforms, but it's 
not designed to do so.  Instead, it's to _reduce_ timer resolution 
compared to what nginx does by default, see 
http://nginx.org/r/timer_resolution.

-- 
Maxim Dounin
http://nginx.org/