On Thu, Nov 01, 2012 at 06:43:28PM +0100, Arend van Spriel wrote: > On 10/26/2012 04:23 PM, Seth Forshee wrote: > >The brcmsmac internal tx buffering is problematic for a number of > >reasons. The amount of buffering is excessive (228 packets in addition > >to the 256 slots in each DMA ring), frames may be dropped due to a lack > >of flow control, and the structure of the queues complicates the > >otherwise straightforward mapping of mac80211 queues to device fifos. > > > >This patch reworks the transmit code path to eliminate the internal > >buffering. Frames are immediately handed off to the DMA support rather > >than passing through an intermediate queue. ieee80211_(stop|wake)_queue() > >are used for flow control to stop receiving frames when a DMA tx ring is > >full. > > > >To handle aggregation the concept of AMPDU sessions is added to the > >driver. The AMPDU session allows MPDUs to be temporarily queued by the > >DMA code until either a full AMPDU has been collected or circumstances > >dictate that transmission should start with a partial AMPDU. The use of > >a queue ensures that the tx headers are fully initialized before the > >buffers are synced for DMA, and it allows non-aggregate frames to be > >immediately placed in the tx ring so that more frames can be collected > >for aggregation. > > > >Signed-off-by: Seth Forshee <seth.forshee@xxxxxxxxxxxxx> > >--- > > drivers/net/wireless/brcm80211/brcmsmac/ampdu.c | 666 ++++++++++------------- > > drivers/net/wireless/brcm80211/brcmsmac/ampdu.h | 29 +- > > drivers/net/wireless/brcm80211/brcmsmac/dma.c | 182 ++++++- > > drivers/net/wireless/brcm80211/brcmsmac/dma.h | 9 +- > > drivers/net/wireless/brcm80211/brcmsmac/main.c | 514 +++++------------ > > drivers/net/wireless/brcm80211/brcmsmac/main.h | 39 +- > > drivers/net/wireless/brcm80211/brcmsmac/types.h | 1 - > > 7 files changed, 628 insertions(+), 812 deletions(-) > > Hi Seth, > > The idea behind the change is a good move. However, this change is > quite a overhaul especially for ampdu code. This makes it pretty > hard to review. At least against the previous implementation. So we > still need some time to chew on this one. We have been testing it > and it looks good there. Great! The AMPDU changes do look significant, but in large part they're just rearranging the code. > Could you somehow split this change into smaller steps? I'd given a little thought to breaking it up before I sent the patches, but for the bulk of the changes it's a little challenging to do so without making some of the commits regress (e.g. break AMPDU in one commit then fix it in the next one). I'll take a closer look while I'm travelling and see if I can work something out. Thanks, Seth -- 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
