On Tue, Oct 02, 2007 at 10:14:11AM -0700, Rick Jones wrote: > Larry McVoy wrote: > >A short summary is "can someone please post a test program that sources > >and sinks data at the wire speed?" because apparently I'm too old and > >clueless to write such a thing. > > WRT the different speeds in each direction talking with HP-UX, perhaps > there is an interaction between the Linux TCP stack (TSO perhaps) and > HP-UX's ACK avoidance heuristics. If that is the case, tweaking > tcp_deferred_ack_max with ndd on the HP-UX system might yield different > results.
I doubt it because I see the same sort of behaviour when I have a group of Linux clients talking to the server. The HP box is in the mix simply because it has a gigabit card and that makes driving the load simpler. But if I do several loads from 100Mbit clients I get the same packet throughput. > WRT the small program making a setsockopt(SO_*BUF) call going slower than > the rsh, does rsh make the setsockopt() call, or does it bend itself to the > will of the linux stack's autotuning? What happens if your small program > does not make setsockopt(SO_*BUF) calls? I haven't tracked down if rsh does that but I've tried doing it with values of default, 64K, 1MB, and 10MB with no difference. > *) depending on the quantity of CPU around, and the type of test one is These are fast CPUs and they are running at 93% idle while running the test. -- --- Larry McVoy lm at bitmover.com http://www.bitkeeper.com - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html