Am Montag, 2. Juli 2007 schrieb Alan Stern: > On Mon, 2 Jul 2007, Oliver Neukum wrote: > > > > I don't think so. For one thing, we'd be allocating fewer URBs. For > > > another, the total number of submissions would be the same; they would > > > just be spread out in time instead of all at once. > > > > But the number of interrupts would grow. The ideal number of interrupts > > per transfer is 1. If you can avoid using more by using a bit more > > memory, is a wiÅning strategy. > > Currently the number of interrupts per transfer is larger than 1. Of > course we can change that, but should we? On small systems, saving a > little CPU time by using a lot more memory is not a win.
It is the current design goal. The sg code requests an interrupt only for the last element of the scatter list. > > > Actually, the best way to approach this would be to relax the guarantee > > > that completion routines are called with interrupts disabled. There's > > > no real reason for that guarantee; it's just an historical remnant. > > > > It speeds up execution in real interrupts, which is good. > > I don't buy that. Leaving interrupts disabled 90% of the time would > also speed up execution. But it would ruin latency. > > > Completion handlers might be called in a bottom half, but this > > is a rather intrusive change. > > We don't need bottom halves. Just remove the guarantee that interrupts > will be disabled. OK, very well. How shall we split the audit load? I volunteer for drivers/usb/serial Regards Oliver ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel