Re: [ANNOUNCE] VM Regress - A VM regression and test tool

[Helge Hafting <helgehaf@aitel.hist.no>]

Rik van Riel wrote:

> The thing is that developers need some benchmarking thing
> they can script to run overnight.  Watching vmstat for
> hours on end is not a useful way of spending development
> time.
> 
> On the other hand, if somebody could code up some scriptable
> benchmarks that approximate real workloads better than the
> current benchmarks do, I'd certainly appreciate it.
> 
> For web serving, for example, I wouldn't mind a benchmark that:
> 
> 1) simulates a number of users, that:
>     1a) load a page with 10 to 20 associated images
>     1b) sleep for a random time between 3 and 60 seconds,
>         "reading the page"
>     1c) follow a link and grab another page with N images
> 2) varies the number of users from 1 to N
> 3) measures
>     3a) the server's response time until it starts
>         answering the request
>     3b) the time it takes to download each full page
> 
> Then we can plot both kinds of response time against the number
> of users and we have an idea of the web serving performance of
> a particular system ... without focussing on, or even measuring,
> the unrealistic "servers N pages per minute" number.
> 
Don't forget to count the total amount of
swap & block io.  (i.e. vmstat 1 > logfile & sum it up)

Good strategies for page replacement may result in
less io for the same job, which means a lot for
performance whenever you get disk-bound.  Many
a web server serves more than fits in cache, and of
course there are file servers too...

Helge Hafting