On Mon, 2009-09-07 at 17:14 -0700, Stephen Hemminger wrote: > On Mon, 7 Sep 2009 15:58:50 -0700 > "Luis R. Rodriguez" <mcgrof@xxxxxxxxx> wrote: > > > A while ago I had read about an effort to consider removing tasklets > > [1] or at least trying to not use them. I'm unaware of the progress in > > this respect but since reading that article have always tried to > > evaluate whether or not we need tasklets on wireless drivers. I have > > also wondered whether work in irq context in other parts of the kernel > > can be moved to process context, a curious example being timers. I'll > > personally be trying to using only process context on bottom halves on > > future drivers but I figured it may be a good time to ask how serious > > was avoiding tasklets or using wrappers in the future to avoid irq > > context is or is it advised. Do we have a general agreement this is a > > good step forward to take? Has anyone made tests or changes on a > > specific driver from irq context to process context and proven there > > are no significant advantages of using irq context where you would > > have expected it? > > > > Wireless in particular should IMHO not require taskets for anything > > time sensitive that I can think about except perhaps changing channels > > quickly and to do that appropriately also process pending RX frames > > prior to a switch. It remains to be seen experimentally whether or not > > using a workqueue for RX processing would affect the time to switch > > channels negatively but I doubt it would be significant. I hope to > > test that with ath9k_htc. > > > > What about gigabit or 10 Gigabit Ethernet drivers ? Do they face any > > challenges which would yet need to be proven would not face issues > > when processing bottom halves in process context? > > > > [1] http://lwn.net/Articles/239633/ > > > > Luis > > -- > > To unsubscribe from this list: send the line "unsubscribe netdev" in > > the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html > > Why not use NAPI, which is soft irq? Almost all 1G and 10G drivers > use NAPI. > > Process context is too slow. Well, I'm hoping to prove the opposite. I'm working on some stuff that I plan to present at Linux Plumbers. I've been too distracted by other things, but hopefully I'll have some good numbers to present by then. -- Steve -- 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
