# Nginx Module Concurrency Query **URL:** \ **Category:** NGINX\ **Created:** [July 1, 2011, 3:40pm UTC](https://www.ruby-forum.com/t/nginx-module-concurrency-query/208975 "2011-07-01T15:40:45Z")\ **Posts on this page:** 3\ **Page:** 1
**Author:** ![luislavena](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/l/0ea827/32.png) [@luislavena](https://www.ruby-forum.com/u/luislavena)\ **Post date:** [July 1, 2011, 3:40pm UTC](https://www.ruby-forum.com/t/nginx-module-concurrency-query/208975/1 "2011-07-01T15:40:45Z")
Hello, I have been trying to get a simple nginx\_module working. I referred [Emiller’s Guide to Nginx Module Development – Evan Miller](http://www.evanmiller.org/nginx-modules-guide.html) and found it very useful. The module takes “[http://10.90.50.31:1257/hello?w=lelj&ljd=22112](http://10.90.50.31:1257/hello?w=lelj&ljd=22112)” and sleeps for few sec and simply prints the URI. ## Here is the code :- #include \ #include \ #include \ #include \ static char \*ngx\_http\_hello\_world(ngx\_conf\_t \*cf, ngx\_command\_t \*cmd, void \*conf); static ngx\_command\_t ngx\_http\_hello\_world\_commands[] = { { ngx\_string(“hello\_world”), NGX\_HTTP\_LOC\_CONF|NGX\_CONF\_NOARGS, ngx\_http\_hello\_world, 0, 0, NULL }, ``` ngx_null_command ``` }; //static u\_char ngx\_hello\_world[] = “elcome world”; static ngx\_http\_module\_t ngx\_http\_hello\_world\_module\_ctx = { NULL, /\* preconfiguration _/ NULL, /_ postconfiguration \*/ NULL, /\* create main configuration _/ NULL, /_ init main configuration \*/ NULL, /\* create server configuration _/ NULL, /_ merge server configuration \*/ NULL, /\* create location configuration _/ NULL /_ merge location configuration \*/ }; ngx\_module\_t ngx\_http\_hello\_world\_module = { NGX\_MODULE\_V1, &ngx\_http\_hello\_world\_module\_ctx, /\* module context _/ ngx\_http\_hello\_world\_commands, /_ module directives _/ NGX\_HTTP\_MODULE, /_ module type _/ NULL, /_ init master _/ NULL, /_ init module _/ NULL, /_ init process _/ NULL, /_ init thread _/ NULL, /_ exit thread _/ NULL, /_ exit process _/ NULL, /_ exit master \*/ NGX\_MODULE\_V1\_PADDING }; int sum(int a, int b) { return a+b; } static ngx\_int\_t ngx\_http\_hello\_world\_handler(ngx\_http\_request\_t \*r) { ngx\_buf\_t \*b; ngx\_chain\_t out; r-\>headers\_out.content\_type.len = sizeof(“text/html”) - 1; r-\>headers\_out.content\_type.data = (u\_char \*) “text/html”; b = ngx\_pcalloc(r-\>pool, sizeof(ngx\_buf\_t)); out.buf = b; out.next = NULL; b-\>pos = (r-\>args).data; b-\>last = (r-\>args).data + (r-\>args).len; b-\>memory = 1; b-\>last\_buf = 1; usleep(1500000); r-\>headers\_out.status = NGX\_HTTP\_OK; r-\>headers\_out.content\_length\_n = (r-\>args).len; ngx\_http\_send\_header(r); return ngx\_http\_output\_filter(r, &out); } static char \*ngx\_http\_hello\_world(ngx\_conf\_t \*cf, ngx\_command\_t \*cmd, void \*conf) { ngx\_http\_core\_loc\_conf\_t \*clcf; clcf = ngx\_http\_conf\_get\_module\_loc\_conf(cf, ngx\_http\_core\_module); clcf-\>handler = ngx\_http\_hello\_world\_handler; ## return NGX\_CONF\_OK; } nginx.conf ########### worker\_processes 4; events { worker\_connections 1024; } … # … # ``` location = /hello { hello_world ; } ``` ######### But I guess, I am missing something here. I tried ab (Apache benchmarking) on it, and I found that response time degrades on increasing concurrency. # ab -c 10 -n 100 “[http://10.90.50.31:1257/hello?w=lelj&ljd=22112](http://10.90.50.31:1257/hello?w=lelj&ljd=22112)” … Time per request: 3804.810 [ms] (mean) … # ab -c 20 -n 100 “[http://10.90.50.31:1257/hello?w=lelj&ljd=22112](http://10.90.50.31:1257/hello?w=lelj&ljd=22112)” … Time per request: 7587.228 [ms] (mean) … # ab -c 30 -n 100 “[http://10.90.50.31:1257/hello?w=lelj&ljd=22112](http://10.90.50.31:1257/hello?w=lelj&ljd=22112)” … Time per request: 11376.207 [ms] (mean) … The response time was 11376ms, 7587ms, 3804ms for 30, 20, 10 concurrency respectively. I am not sure what I am missing. Can someone please guide me on how do I make this module scale? - Danny Posted at Nginx Forum: > **[Nginx Module Concurrency Query](https://forum.nginx.org/read.php?2,211552,211552#msg-211552)** > > Hello, I have been trying to get a simple nginx\_module working. I referred http://www.evanmiller.org/nginx-modules-guide.html and found it very useful. The module takes "http://10.90.50.31:1257/hello?w=lelj&ljd=22112" and sleeps for few... ---
**Author:** ![Danny\_Glover](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/3bc359/32.png) [@Danny\_Glover](https://www.ruby-forum.com/u/Danny_Glover)\ **Post date:** [July 1, 2011, 4:08pm UTC](https://www.ruby-forum.com/t/nginx-module-concurrency-query/208975/2 "2011-07-01T16:08:33Z")
Hello! On Fri, Jul 01, 2011 at 09:40:20AM -0400, Danny Glover wrote: > I have been trying to get a simple nginx\_module working. I referred > [Emiller’s Guide to Nginx Module Development – Evan Miller](http://www.evanmiller.org/nginx-modules-guide.html) and found it very > useful. > > The module takes “[http://10.90.50.31:1257/hello?w=lelj&ljd=22112](http://10.90.50.31:1257/hello?w=lelj&ljd=22112)” and > sleeps for few sec and simply prints the URI. > > Here is the code :- […] > usleep(1500000); […] > The response time was 11376ms, 7587ms, 3804ms for 30, 20, 10 concurrency > respectively. > I am not sure what I am missing. > > Can someone please guide me on how do I make this module scale? The behaviour you see is expected: you can’t sleep as it will block all requests in a worker process. Welcome to event-based programming. 🙂 You have to arm timer and return back to event loop, then continue processing once event fires. You may take a look how to do this in standard limit\_req module, though it will require some adaption for handler module. In particular, you’ll have to return NGX\_DONE and then finalize request yourself, much like it’s done when reading request body. Maxim D. ---
**Author:** ![Danny\_Glover](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/d/3bc359/32.png) [@Danny\_Glover](https://www.ruby-forum.com/u/Danny_Glover)\ **Post date:** [July 5, 2011, 9:29am UTC](https://www.ruby-forum.com/t/nginx-module-concurrency-query/208975/3 "2011-07-05T09:29:47Z")
Hi Maxim, Thank you for the details. I will read through. - Danny Posted at Nginx Forum: > **[Re: Nginx Module Concurrency Query](https://forum.nginx.org/read.php?2,211552,211950#msg-211950)** > > Hello, I have been trying to get a simple nginx\_module working. I referred http://www.evanmiller.org/nginx-modules-guide.html and found it very useful. The module takes "http://10.90.50.31:1257/hello?w=lelj&ljd=22112" and sleeps for few...