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Re: PLEASE HELP regarding System Tap


Hi -

On Tue, Jul 08, 2008 at 05:48:59PM -0700, Khushboo Goel wrote:
> [...]
> I am actually sending some 10Gb or data over 8 tcp connection from 1 cpu ..
> But its post calculation so i don't think so i wana get into that ...

The overall quantity of network traffic should not matter.  The
histograms should work simply as counters of packet sizes.


> >> Is it possible i can know what address location is assigned to
> >> system Tap buffer in the memory ??
> >
> > There are many different buffers.  You might be interested in the one
> > the runtime can hand over via _stp_reserve(), but using that is not
> > routinely recommended.
> 
> Can you tell me more about it or any documentation on it ??? i want to
> go this runtime memory and write there directly.

This is unlikely to accomplish what you want.  It is an internal
interface, so there is no external documentation on it.


> I have observed one more thing , with the aggregate being in the code,
> and i just remove one of the embedded C code , i don't get any buffer
> overflow error, and it prints histogram and everything even for 20Gb
> of data .. with NAGLE off and sending 64 Bytes packet ( 96Bytes
> inclusive of header )
> Which is strange coz i expected aggregate to show overflow buffer error


We really need to see the exact error messages and the exact script
variants you are running, to help you better.  You're doing some good
work exploring these boundaries, but we really need the raw
information to help figure this out.


- FChE


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