[Koha-devel] "The Plack effect" benchmarked

[Tomas Cohen Arazi]

On Wed, Jun 6, 2012 at 10:10 AM, Paul Poulain <paul.poulain at biblibre.com> wrote:
> Le 06/06/2012 13:36, Mark Tompsett a écrit :
>> Greetings,
> Hi Mark,
> (answer to koha-devel, as it's of general interest)
>
>> These results look good, but how much memory is on the machine you are
>> testing this on? Would it have the same effect in a VM server type
>> environment limited to 204MB? Is there an amount of memory which makes
>> it behave at similar or worse speeds?
> I think you missed a 8, and speak of 2048 and not 204MB :D
>
> I haven't tested/checked memory, but what I know for sure is that it
> costs only a small amount of memory.
>
> Plack pre-load a lot of things that are loaded on every page by cgi-bin
> anyway. So you would have 'spent' that memory at run time.
>
> Depending on Apache configuration, if 5 ppl are requesting a page at the
> same time, 5 cgi-bin are launched and 5x memory is consummed. So if you
> run starman instead of plackup (starman being multi-thread, plackup
> single thread), the result will be the same.
>
> What we have to be *very* careful with is memory hole that result in an
> always increasing memory consumption. In CGI mode, as everything is
> freed/deleted after each page, any memory hole is painless. With plack,
> memory hole will pile up and, at the end ... booom !

This is usually addressed by setting some reasonable amount of
requests lifespan for the processes. Anyway, we shouldn't have memory
holes!

Regards
To+