Web torture results

[Elliot Lee]

Hey Ahmed,

It's neat to see these results! A few comments:

I don't see anywhere where variables such as the file size, request  
size, HTTP pipelining, etc. are taken into account. Optimally, the  
test would have cases that exercise points along all these  
dimensions. E.g. a load test of serving an empty file would help us  
understand what the absolute best case performance is within the  
constraints the current systems.

The other thing that'd be useful to have is a well-defined capacity  
goal that helps everyone understand where things ought to be. For a  
straw-man example, let's say 20 home page loads/second, including all  
associated image/CSS/JS files, by logged-in users. I don't know what  
the actual needs are, but a look at the web logs during the FC6  
release should help.

 From what's mentioned below, I also didn't quite understand whether  
squid was sitting in front of apache serving straight HTML/PNG/CSS,  
or whether it was moinmoin that contained all the content. Hopefully  
that's just something I missed in an earlier message.

My current favorite treatise on optimizing overall web performance -  
http://www.die.net/musings/page_load_time/

Hope this helps,
-- Elliot

On Dec 23, 2006, at 3:19 PM, Ahmed Kamal wrote:

> Hi,
> Paulo and me (kim0) have been working on testing a caching setup  
> for the wiki. A test migration to Moin 1.5 is complete, squid is  
> now configured as a reverse caching proxy. We've done some stress  
> tests on the current setup. Attached are some extracted results  
> that (I think) are of interest. Mainly the number of requests  
> served per second, and the average time for serving a request.  
> Also, paulo pointed that caching differs per file type, the tests  
> have been done on three different file types (html, png image, and  
> css)
>
> Test Setup:
> =========
> 1- All connections were initiated from proxy1
> 2- Proxy2 had squid caching turned on
> 3- Testing for html/png/css done, sweeping the number of concurrent  
> connections
> 4- Turn off squid caching on proxy2
> 5- Testing for html/png/css done, sweeping the number of concurrent  
> connections again
>
> Interesting notes:
> ============
> 1- Serving PNG is 10X faster than html
> 2- Serving CSS is 10X faster than PNG!
> 3- Serving html is really the bottleneck. Unfortunately, Moin  
> developers acknowledged current version ( 1.5) is not cache  
> friendly. Work for making 1.6 cache friendly is undergoing
> 4- Using squid currently only seems to double our PNG serving rate,  
> nothing else
> 5- The application server hits swapping (about 0.5GB) at full load  
> (~300 concurrent connections), for some reason the requests/second  
> served is still high!! (Is our cache disks that fast)
> 6- The test did not stress the server bad enough to run out of swap  
> space, not sure if this is needed though!
>
> I can send the full results date if anyone is interested.
>
> Best Regards
> <results.ods>
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