response times and network io

[Denis S. Filimonov]

You are using a tiny file (robots.txt) for your measurements, which means HTTP 
headers constitute large part of the traffic and may well account for 10-15% 
difference.

Denis.

On Friday 29 February 2008 16:54:09 Joe Williams wrote:
> Understood, thanks for the insight. The Nginx was consistently 10 to 15%
> lower than Apache, such as 98MB/s versus 110MB/s.
>
> If you would like to see my results for httperf you can download the
> spreadsheet here:
> http://www.joeandmotorboat.com/wp-content/files/bench_results-comb-static.o
>ds
>
>
> I also posted about it here:
> http://www.joeandmotorboat.com/2008/02/28/apache-vs-nginx-web-server-perfor
>mance-deathmatch/
>
>
> Let me know what you think.
>
> Thanks.
> -Joe
>
> Igor Sysoev wrote:
> > On Fri, Feb 29, 2008 at 11:05:37AM -0600, Joe Williams wrote:
> >> I used httperf to give me the network I/O (KB/s) and response times. I
> >> could probably produce the sar data from each if you would like it. I
> >> assume the response times are due to Nginx not needing to take time to
> >> start up another process/thread?
> >
> > So nginx's network I/O is for example, 20M/s, while Apache's - 100M/s ?
> >
> > In this case network I/O and response times are the same things.
> > The lesser response times, the more you can get for the same time.
> >
> > Apache usually does not start new processes, it has some number of
> > already preforked processes ready to handle requests.
> >
> >> Igor Sysoev wrote:
> >>> On Thu, Feb 28, 2008 at 08:24:24PM -0600, Joe Williams wrote:
> >>>> please excuse my typo. regarding network I/O nginx uses consistently
> >>>> lower I/O than apache.
> >>>>
> >>>> regardless i am curious about how it processes requests differently to
> >>>> obtain lower response times and network I/O.
> >>>
> >>> How do you measure network I/O ?
> >>>
> >>> In short, Apache and nginx use different model for processing requests.
> >>> Apache processes connection in one process or thread while nginx
> >>> processes thousand connections in one process/thread using scaleable
> >>> methods such as kqueue/epoll/etc.
> >>>
> >>>> thanks for any help you can provide.
> >>>>
> >>>> -Joe
> >>>>
> >>>> Joe Williams wrote:
> >>>>> i am performing some httperf tests against apache and nginx.
> >>>>> something i noticed that piqued my interest were the consistency of
> >>>>> response times (0.4 ms each run regardless of number of request, much
> >>>>> lower than apache in all cases) and network I/O (consistently higher
> >>>>> than apache regardless of number of request). it also uses less cpu
> >>>>> than apache and doesn't nearly drive up the load.
> >>>>>
> >>>>> are these normal results? is there a mechanism in nginx that keeps
> >>>>> the response times low and consistent? also, is it normal that it
> >>>>> uses more network I/O? if so, what is the cause? to me it would seem
> >>>>> like that it uses more bandwidth to respond to the same number of
> >>>>> requests which seems inefficient.
> >>>>>
> >>>>> please correct me if i am wrong. i am just trying to understand the
> >>>>> core differences in how nginx works in comparison to apache and why i
> >>>>> would see these performance differences.
> >>>>>
> >>>>> thanks for the help.
> >>>>>
> >>>>> -joe
> >>>>
> >>>> --
> >>>> Name: Joseph A. Williams
> >>>> Email: joe at joetify.com
> >>
> >> --
> >> Name: Joseph A. Williams
> >> Email: joe at joetify.com



-- 
Denis.