Hi Stefan, thank you for the response and the pointers. My replies are inline:
On Sun, Jan 26, 2014 at 1:20 PM, Stefan Sperling <s...@openbsd.org> wrote: > > I believe the rate adaptation code decides to drop performance > in noisy environments (i.e. most major cities where virtually > every flat is now hosting an access point on the 2.4Ghz band). > But I'm speculating and haven't truely investigated this yet. > If you're interested in digging into this, you could study > ieee80211_rssadapt.h and ieee80211_rssadapt.c, and figure out if the > algorithm and its implementation are accurate (I wouldn't rule out > bugs in this code), and if there are better alternatives we could use. > Dragonflybsd have done some work in this area, and I would bet Linux > and FreeBSD have done so, too. I will try to look at it, although I'm quite new to this topic, so the first step is to educate myself and to understand the framework. >> I don't see any reference of the Tx power/gain or Rx gain settings in the >> logs. >> How could I check if the card is performing as intended? > > Depends on what you want to measure and under which conditions. > Range? Packets per seconds? With/without much interference? > All these factors influence each other. Wireless performance is generally > a lot harder to measure than wired. Just because it says 54Mbit/s on the > box doesn't mean you'll get that. Radio is a shared medium. This is exactly why I formulated my questions as suspicions, I noticed that my high power card with high gain antennae provides similar range and signal levels as a standard wireless router, but I don't have exact measurements. I will try to dig deeper. > Of course, if Linux or other BSDs give you better wireless performance > during testing, it may well be that their driver or wireless stack is > doing things we could do as well. > > But someone (you?) will have to dig into this and fix it, or nothing > will change. Slow wifi is better than no wifi at all, so I'm trying > every now and then to enhance our wifi driver support, which has started > falling behind badly since Damien left the project. But I cannot spend > much of my time on this. I'm willing to help where possible, of course. I'll try to experiment with my equipment, and I'll report my findings (and recommendations/patches, should I have any). Based on this discussion, the problems that I encountered are actually two, maybe separate issues: 1) rate adaptation issues, which generally affect access points, 2) card specific issues, which may affect Tx/Rx gain settings (or something completely different) At first, I'm planning to install Linux and/or other BSDs on my box to investigate the differences. If I find significant differences, I'll try to compare the implementations to see what is done differently. Of course I can't promise that I can come up with anything useful, but hopefully something could be improved. Best regards, Marton
