Public bug reported: As mentioned in bug #292054 the performance of the ath5k driver is very poor. This was tested under Jaunty. Comparison points are 1) time to associate with an AP 2) bandwidth on large file transfer from test laptop to local server 3) ping time whilst large file transfer is in progress. Results:
1) Comparison of time to associate with an AP, comparing ath5k to zd1211rw on otherwise identical hardware, results show a statistically significant mean time (from starting NetworkManager to binding an IP address) of 21 seconds versus 9 seconds respectively. Even accounting for minor hardware differences (Atheros versus Zydas chipset) the performance difference should not be so large. 2) Send large file. 100MB file transfer from laptop, comparing ath5k to ath_pci. Transfer is to a local unused PC which is directly connected to the wireless AP via ethernet. ath5k mean bandwidth is 800kb/sec, ath_pci bandwidth is 1.9MB/sec. 3) Comparison of ping time whilst transferring a 100MB file, comparing Atheros ath5k to Zydas zd1211rw on otherwise identical hardware. With zd1211rw, ping is from 1ms to 35ms, bandwidth is 2.1MB/s. With ath5k, ping is from 1ms to 3500ms, bandwidth is 573KB/s. 4) Receive large file. 100MB file transfer to laptop. ath_pci bandwidth is 2.2MB/s ath5k bandwidth is 1.5MB/s. It seems clear that there are performance problems with ath5k, not only comparing against other hardware and drivers, but also some regression from the old ath_pci driver - ath5k is faster to associate than ath_pci, which took around 60s, but bandwidth is slower. Causes of the problem: 1) Bugs that have been already fixed in ath5k. The mean receive bandwidth of compat-wireless-2009-03-03 is 1.43MB/s, compared to 1.04MB/s for the 2.6.28-8 driver. The difference is highly statistically significant, so this is certainly a problem. The drivers and/or kernel should be updated to fix this. 2) According to http://wireless.kernel.org/en/users/Drivers/ath5k "MadWiFi and ndis drivers perform better on noisy environments than ath5k because we don't support Adaptive Noise Immunity (ANI) yet." This may account for other performance loss. ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- Jaunty ath5k poor performance https://bugs.launchpad.net/bugs/337311 You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
