Re: BUG: Slowdown on 3000 socket-machines tracked down

[Ben Greear]

Nick Piggin wrote:
> Ben Greear wrote:
>
> > Christian Schmid wrote:
> >
> > > Ben Greear wrote:
>
>
> > > > How many bytes are you sending with each call to write()/sendto() 
> > > > whatever?
> > >
> > >
> > >  
> > > I am using sendfile-call every 100 ms per socket with the poll-api. 
> > > So basically around 40 kb per round.
> >
> >
> >
> > My application is single-threaded, uses non-blocking IO, and 
> > sends/rcvs from/to memory.
> > It will be a good test of the TCP stack, but will not use the sendfile 
> > logic,
> > nor will it touch the HD.
>
> I think you would have better luck in reproducing this problem if you
> did the full sendfile thing.
>
> I think it is becoming disk bound due to page reclaim problems, which
> is causing the slowdown.
>
> In that case, writing the network only test would help to confirm the
> problem is not a networking one - so not useless by any means.

It's not trivial to write something like this :)

I'll be using something I already have.  If I can't reproduce the problem,
then perhaps it is due to sendfile and someone can write a customized
test.  The main reason I offered is because people are ignoring the
bug report for the most part and asking for a test case.  I may be able
to offer an independent verification of the problem which might convince
someone to write up a dedicated test case...

Ben


--
Ben Greear <greearb@xxxxxxxxxxxxxxx>
Candela Technologies Inc  http://www.candelatech.com

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