Hi On Tue, Mar 06, 2012 at 06:43:56PM +0100, Martin Hundebøll wrote: > Hi, > > On 03/05/2012 05:48 PM, Stanislaw Gruszka wrote: > >Is possible that we stop queue and then do not wake up it again, > >especially when packets are transmitted fast. That can be easily > >reproduced with modified tx queue entry_num to some small value e.g. 16. > > > >If mac80211 already hold local->queue_stop_reason_lock, then we can wait > >on that lock in both rt2x00queue_pause_queue() and > >rt2x00queue_unpause_queue(). After drooping ->queue_stop_reason_lock > >is possible that __ieee80211_wake_queue() will be performed before > >__ieee80211_stop_queue(), hence we stop queue and newer wake up it > >again. > > > >To prevent stalls serialize pause/unpause by queue->tx_lock. > > I've been having CPU load issues with rt2800usb/Ralink RT2870, when doing simultaneous TX/RX between to nodes in an adhoc network. While transfering UDP packets in one direction with iperf[1], I get ~23Mbit/s and kworker is utilizing <10% of the CPU (OMAP4 1GHz dualcore or/and Pentium M 1.70GHz) on both ends. When doing bidirectional tests with iperf[2], one kworker thread jumps too 100% and throughput drops. > > By using two iperf clients to do bidirectional TCP transfers, I got ~6Mbit/s in both directions, so I suspected some queueing issues and thus applied this patch, but no change. I've tried to do some tracing[3], but this is quite new to me, so please instruct me, if you need more info. I did short test here and do not enter that issue. Which kernel version are you using? > [3] > out.txt has a trace from 10.10.10.55 while running iperf as in [2] and the following commands: Please newer do this again :-) If you want to provide such big data, put it somewhere and paste download link to the email. Moreover that tracing did not provide any useful information. Stanislaw -- 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
