Re: [take22 0/4] kevent: Generic event handling mechanism.

["Nate Diller" <nate.diller@gmail.com>]

On 11/1/06, Evgeniy Polyakov <johnpol@2ka.mipt.ru> wrote:
> On Wed, Nov 01, 2006 at 06:20:43PM +0000, Oleg Verych (olecom@flower.upol.cz) wrote:
> >
> > Hallo, Evgeniy Polyakov.
>
> Hello, Oleg.
>
> > On 2006-11-01, you wrote:
> > []
> > >> Quantifying "how much more scalable" would be nice, as would be some
> > >> example where it is useful. ("It makes my webserver twice as fast on
> > >> monster 64-cpu box").
> > >
> > > Trivial kevent web-server can handle 3960+ req/sec on Xeon 2.4Ghz with
> > [...]
> >
> > Seriously. I'm seeing that patches also. New, shiny, always ready "for
> > inclusion". But considering kernel (linux in this case) as not thing
> > for itself, i want to ask following question.
> >
> > Where's real-life application to do configure && make && make install?
>
> Your real life or mine as developer?
> I fortunately do not know anything about your real life, but my real life
> applications can be found on project's homepage.
> There is a link to archive there, where you can find plenty of sources.
> You likely do not know, but it is a bit risky business to patch all
> existing applications to show that approach is correct, if
> implementation is not completed.
> You likely do not know, but after I first time announced kevents in
> February I changed interfaces 4 times - and it is just interfaces, not
> including numerous features added/removed by developer's requests.
>
> > There were some comments about laking much of such programs, answers were
> > "was in prev. e-mail", "need to update them", something like that.
> > "Trivial web server" sources url, mentioned in benchmark isn't pointed
> > in patch advertisement. If it was, should i actually try that new
> > *trivial* wheel?
>
> Answer is trivial - there is archive where one can find a source code
> (filenames are posted regulary). Should I create a rpm? For what glibc
> version?
>
> > Saying that, i want to give you some short examples, i know.
> > *Linux kernel <-> userspace*:
> > o Alexey Kuznetsov  networking     <-> (excellent) iproute set of utilities;
>
> iproute documentation was way too bad when Alexey presented it first
> time :)
>
> > o Maxim Krasnyansky tun net driver <-> vtun daemon application;
> >
> > *Glibc with mister Drepper* has huge set of tests, please search for
> > `tst*' files in the sources.
>
> Btw, show me splice() 'shiny' application? Does lighttpd use it?
> Or move_pages().
>
> > To make a little hint to you, Evgeniy, why don't you find a little
> > animal in the open source zoo to implement little interface to
> > proposed kernel subsystem and then show it to The Big Jury (not me),
> > we have here? And i can not see, how you've managed to implement
> > something like that having almost nothing on the test basket.
> > Very *suspicious* ch.
>
> There are always people who do not like something, what can I do with
> it? I present the code, we discuss it, I ask for inclusion (since it is
> the only way to get feedback), something requires changes, it is changed
> and so on - it is development process.
> I created 'little animal in the open source zoo' by myself to show how
> simple kevents are.
>
> > One, that comes in mind is lighthttpd <http://www.lighttpd.net/>.
> > It had sub-interface for event systems like select,poll,epoll, when i
> > checked its sources last time. And it is mature, btw.
>
> As I already told several times, I changed only interfaces 4 times
> already, since no one seems to know what we really want and how
> interface should look like.

Indesiciveness has certainly been an issue here, but I remember akpm
and Ulrich both giving concrete suggestions.  I was particularly
interested in Andrew's request to explain and justify the differences
between kevent and BSD's kqueue interface.  Was there a discussion
that I missed?  I am very interested to see your work on this
mechanism merged, because you've clearly emphasized performance and
shown impressive results.  But it seems like we lose out on a lot by
throwing out all the applications that already use kqueue.

NATE