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

Nick Piggin
2005-03-07T05:14:57Z

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.