Christian Schmid wrote:

Hmmmm.... can you try to following just to exclude some theories:

Run it with 4000 sockets and then do the following on the server-machine:

dd if=/dev/zero of=file1 bs=1M count=1024
dd if=/dev/zero of=file2 bs=1M count=1024
dd if=/dev/zero of=file3 bs=1M count=1024
cat file1 > /dev/zero & cat file2 > /dev/zero & cat file3 > /dev/zero &

I THINK it might have something to do with caching-pressure or so. See if there is a slow-down on the sending if the page-cache gets full and has to be cleared again.

You are running 2.6.11?

Yes, 2.6.11. I have tuned max_backlog and some other TCP and networking related settings to give more buffers etc to networking tasks. I have not tried any significant disk-IO while doing these tests.

I finally got my systems set up so I can run my WAN emulator at full 1Gbps:

I am getting right at 986Mbps throughput with 30ms round-trip latency
(15ms in both directions).

So, latency does not seem to be the problem either.

I think the problem can be narrowed down to:

1)  Non-optimal kernel network tunings on your server.
2)  Disk-IO (my disk is small and slow compared to a 'real' server, not sure I 
can
     really test this side of things, and I have not tried as of yet.)
3)  Your clients have much more latency and/or don't have enough bandwidth
     to fully load your server.  Since you didn't answer before:  I assume you
     do not have a reliable test bed and are just hoping that enough clients 
connect
     to do your benchmarking.
4)  There is something strange with sendfile and/or your application's coding.

My suggestion would be to eliminate these variables by coming up with a 
repeatable
test bed, alternative traffic generators, WAN/Network emulators for latency, 
etc.

Thanks,
Ben

--
Ben Greear <[EMAIL PROTECTED]>
Candela Technologies Inc  http://www.candelatech.com

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to