Messages in this thread | | | From | (Alan Cox) | Subject | Re: select()/socket has problems under 2.2.x. | Date | Tue, 27 Apr 1999 18:49:28 +0100 (BST) |
| |
> 1. When txqueuelen is set low (e.g. <=10) the queue into the ppp0 device overflows and packets are > occasionally lost. This explains the mysterious missing-packet problem I provided tcpdumps for. > Increasing txqueuelen "fixed" that problem.
You want to lower it (see 3)
> retrain, which lasts a few seconds each, the errored bits cause an internal modem retransmit, > delaying logical delivery of the data to Linux by a few hundred milliseconds at a time. This timing > variability, which is not Linux's fault, exacerbates (I hypothesize) a third problem:
If you get a lot of retrains fix your phone line 8) but also check your manuals. You can tell the modem to refuse to retrain down a speed but to keep the current speed on most modems.
> ensure that packets aren't dropped due to overflows of the outgoing buffer? If not, wouldn't it be > better to keep txquueuelen high and just grin and bear the latency for interactive use?
Generally lower txqlen is better. It speeds up feedback
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |