-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Maxim Levitsky a écrit : > Derek Smithies wrote: >> Hi, >> to verify that it is a rate control issue, there is one very simple and >> very practical test. >> >> Take both ends of your link, and set them to fixed rate, and at the rate >> you think it should be achieving. >> If you can achieve significantly higher throughputs with fixed rate, you >> know that the rate control algorithm (or interface with rate algorithm) >> has failed. >> >> Derek. >> >> On Fri, 21 Nov 2008, Bob Copeland wrote: >> >>> On Fri, Nov 21, 2008 at 10:28:29PM +0200, Maxim Levitsky wrote: >>>> I initially blamed iwl3945, then thought it got fixed, but now I have >>>> ath5k, and speeds are low >>>> and I suspect that both drivers has bugs regarding to speed. >>> Quite possible, but both use mac80211 for rate control. Which rate >>> control algorithm are you using? > Hi, > > Well, iwl3945 was showing 54M all the time in iwconfig, > also it doesn't support setting fixed rate, at least not using iwconfig. > > ath5k never shows higher that 18M, and supports setting fixed rate, but if I set it to anything higher that 18M, > speeds drop to 0Kbytes/s immediately. > Speeds lower that 18M work, and affect throughput accordantly > For most of tests speeds are ether 18M or lower, but then when I set them to 18M this didn't increase throughput. > > iwl3945 was always at 54M > > > > Best regards, > Maxim Levitsky I did a similar test here and results is very strange. AP was my good old linksys WRT54G running an iperf server. Client was a laptop running either ath5k or madwifi/trunk and an iperf client. Channel is 5. Both drivers show the same behaviour. At the beginning, throughput was very low : 500 - 600 kbit/s. Suddenly (after few minutes), it jumps to 15 - 17 Mbit/s and then few minutes later (let's say 10 - 20 minutes maybe), it jumps back to 500 - 600 kbit/s. Using a fixed rate has no effect. I used my latest wireless monitoring tools and I did not saw lost of duplicates or lost packets. The only difference was the number of packets sent by seconds.... Looking a my syslog, I just saw few messages, unrelated in time with the throughput going up or down. They were: - - ath5k : unsupported jumbo - - switching to short barker preamble - - switching to long barker preamble I can repeat the same test with iwl3945 as well, if needed. Regards, Benoît -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFJKlkTOR6EySwP7oIRAnR1AJ0UCiENM0qtZwQYngkVpiLvrKtgLACfRKPz Wi/HreSX4NV+kfyeS+RMFaY= =RKcV -----END PGP SIGNATURE----- -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
