Messages in this thread | | | Date | Wed, 31 Mar 2004 10:50:39 -0800 | From | Stephen Hemminger <> | Subject | Re: Powers-of-two - 7 for recv() length?? |
| |
On Wed, 31 Mar 2004 13:02:03 -0500 (EST) "Richard B. Johnson" <root@chaos.analogic.com> wrote:
> On Wed, 31 Mar 2004, Stephen Hemminger wrote: > > > What is the socket send/receive buffering, and the underlying network. > > You need to look at the data flow with something like tcpdump and tcptrace. > > If you get flow controlled or lots of other reasons, TCP will validly > > send a small number of bytes (like 1) which will get things out of alignment. > > > > Hmmm. I get lots of truncated IP packets. See attached. I've tried > to help by setting both RCV_BUF and SND_BUF to 1/2 megabytes. Nothing > seems to work except sending only 1436 bytes at a time. That makes > everything miserably slow. 1436 comes from (1500 - 64) 1500 being the > ethernet packet length, 64 being the IP header length. >
That is because you are running on the loopback interface that has an MTU of 16K. And tcpdump is being smart and only reading part of the data.
> Cheers, > Dick Johnson > Penguin : Linux version 2.4.24 on an i686 machine (797.90 BogoMips). > Note 96.31% of all statistics are fiction. > >
-- Stephen Hemminger mailto:shemminger@osdl.org Open Source Development Lab http://developer.osdl.org/shemminger - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |