On 10/26/2012 04:23 PM, Seth Forshee wrote: > I've been looking into the issues with brcmsmac performance reported at > [0] and [1]. I started out looking into the tx queueing based on the "No > where to go" messages in the logs. This code has a number of > shortcomings: > > - The amount of bufferring is excessive. The tx queue will buffer up to > 228 packets, and each of the tx DMA rings will queue up to 256 more. > > - There's no flow control. If the queue fills up packets begin to get > dropped, as evidenced by the "No where to go" messages. > > - Without flow control the tx queue probably helps avoid dropping > packets for short bursts due to the sheer number of packets that will > be buffered, but if flow control is added the only remaining benefit > that I can see is that it accumulates packets for aggregation. The tx > queue is far more complex than needed for supporting aggergation, > however. > > As a result I worked up the following patches to add flow control remove > the tx queue. > > These patches change the tx handler to directly hand off packets to the > DMA code. The convoluted priority->precedence->fifo mapping is converted > to a simple one-to-one mapping of the mac80211 queues to fifos. Non- > aggregate frames are immediately inserted into the DMA ring. I mentioned earlier we were still looking at the first patch in this series and do more testing on it. However, I wanted to provide feedback on the other patches now. See below. > Thanks, > Seth > > [0] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1046507 > [1] http://www.spinics.net/lists/linux-wireless/msg96287.html > > > Seth Forshee (18): > brcmsmac: Rework tx code to avoid internal buffering of packets under test > brcmsmac: Use correct descriptor count when calculating next rx > descriptor nice catch. acked. > brcmsmac: Reduce number of entries in tx DMA rings under test. > brcm80211: Allow trace support to be enabled separately from debug A bit confusing with BRCMDBG selecting BRCMS_TRACING. > brcm80211: Add macro for checking if debug log levels are enabled During mainlining we got rid of such a macro. Strange to put something similar back in there. > brcm80211: Convert log message levels to debug levels acked. > brcmsmac: Add module parameter for setting the debug level I would prefer doing this through debugfs. > brcmsmac: Add support for writing debug messages to the trace buffer can you name the new files just debug.[ch] > brcmsmac: Use debug macros for general error and debug statements acked. > brcmsmac: Add BRCMS_DBG_MAC80211 debug macro > brcmsmac: Add RX and TX debug macros > brcmsmac: Add INT debug macro > brcmsmac: Add DMA debug macro > brcmsmac: Add HT debug macro I would prefer the macros to be in lower case. > brcmsmac: Improve tx trace and debug support acked. > brcmsmac: Add tracepoint for macintstatus useful one. acked. > brcmsmac: Add tracepoint for AMPDU session information acked. > brcmsmac: Remove some noisy but uninformative debug messages acked. I would say: noisy *and* uninformative but that is just semantics ;-) Regards, AvS -- 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
