Measuring response times is important, but so is measuring the effect of the load on the server(s) themselves. You also want a good record of when responses fail outright, because if you push the system far enough that will start to happen.
But just as important, you want to know what's happening in the SUT when the response times go south. What's the bottleneck? was it your database? file-io? did you overhelm a middle-tier server? did you generate so much traffic it saturated the internet network connection? (or would have) What's the weakest link in your chain, and how was the rest of the chain holding up? You want a really good record of those numbers so when you run the test again after making an adjustment, you can verify that the adjustment had the desired effect, and also that nothing else was suddenly out of wack (e.g. the other numbers from outside the area where you made your tweek should be substantially the same as the prior run. On Apr 3, 2:28 am, JArkelen <[email protected]> wrote: > I created my own tool which generates "dumb" HTTP requests to the > server, combined with one watir user at the same time doing the actual > measuring of response times. Because I also use the HTTPwatch API, I > can report on both HTTP response times and real-user response times. > Best of both worlds! > > Cheers, > John > > On Apr 3, 4:33 am, Chuck van der Linden <[email protected]> wrote: > > > > > On Apr 2, 2:01 pm, Paul Rogers <[email protected]> wrote: > > > > most load tools do direct http posts/gets/put requests. jmeter does this > > > using a java library, to get the high levels of virtual users. > > > Browsermob uses amazon cloud running ms windows 2003 server and a real > > > browser. > > > Paul is absolutely right in this regard. This is because the overhead > > of rendering and running client side code means if you use anything > > remotely resembling a 'real browser' it won't scale well, and you will > > need a small fleet of systems to generate the load. > > > It's also un-necessary. some vendors who don't support protocol level > > load will try to justify their tool as being 'more realistic' which I > > say is utter one-hundred percent hogwash. The server has NO idea who > > is sending those packets, and it can't tell IE or Firefox from a good > > tool claiming to be IE or Firefox.. the 'realism' is all in the mind > > of the salesman because the web server hasn't a clue. > > > > Ive think the best way of doing load tests is to use jmeter or other tool. > > > You may be able to record a script via the jmeter proxy when watir is > > > running. I can see a lot of advantages to this, but it takes a lot of hand > > > editing to go and make the recorded jmeter script usable for more than one > > > user. > > > > Ive found load testing to be a particulary difficult thing todo. Mostly > > > because of the question "what are we trying to do here?" - find out what > > > bit > > > breaks first? Find out how many users we can support before we need a new > > > bit of hardware? Find out what the slowest operastion is? Find out how to > > > make the slowest operation better? There is a book that Scott Barber was a > > > coauthor of, that is available as a free pdf that is good reading. > > > I agree 100% Paul. load testing and perf testing is some of the more > > 'scientific' testing you can do, it requires close attention to > > detail, tight control over variables, tests that are highly > > reproducable, and as you point out you have to start out by asking the > > right question. A loadtest is basically an experiment, and like any > > experiment it's only going to be as successful as the hypothesis it's > > trying to prove or disprove. If you don't know the question you are > > trying to ask, you're not likely to design loadtest that will give you > > results you can use. > > > As for myself, I've used both loadrunner (really good but really > > expensive) and Microsoft's Visual Studio Team System2008 (both the > > "test edition" and "team suite" versions have a HTTP level web-test > > and loadtest capability) I found in my work that it scales well and > > blows loadrunner away in terms of bang for the buck. I've used it > > with just a single machine as the load generator (also running the > > controller as wel) and brought both webservers and db servers to their > > virtual knees and had they crying uncle! There's also an excellent > > MSDN forum with some of the main pm's etc providing advice and > > support, and a small collection of videos and such. > > > The downside is that it does all the SUT monitoring via WMI > > (Microsoft's implementation of WBEM) which works fabulous on windows > > servers, but because the *nix community never implemented WBEM (a > > multi vendor DMTF standard) there's no performance monitoring daemon > > that allows you to connect to the machine using WBEM, and hence you > > can't monitor the performance of non windows servers, and without good > > (really good) data on how the systems are being affected by the load, > > corrilated with what the scripts are doing, the loadtests are of much > > less value. > > > Sorry but this is a bit of a soapbox for me. it's really ironic in a > > way that the "closed' windows OS, because MS implemented an open > > standard is more accessable in terms of remote monitoring and > > rathering of system information (out of the box without having to > > installl anything, and merely configuring some accounts that are > > allowed to access the data) than the supposedly 'open' os's which > > never adopted that standdard and are thus a relative black hole in > > terms of being able to remotely monitor performance counters > > > --Chuck- Hide quoted text - > > - Show quoted text - --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "Watir General" group. 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