On 9/4/07, jamal <[EMAIL PROTECTED]> wrote: > On Mon, 2007-03-09 at 20:20 -0700, Mandeep Singh Baines wrote: > > > I didn't see much saving in interrupts on my machine (too fast, I guess). > > You could try the idea suggested by Dave earlier and just turn interupts > for every nth packet. That should cut down the numbers. >
I wanted to do that but I couldn't figure out how to free the last skb if it happened to be a transmit that didn't generate a tx completion interrupt. Let's say I interrupt every 4th packet.I've already sent packets 0 to 4. Now I send packets 5 and 6. I can't figure out how to ensure that the skb's for these packets get freed in a deterministic amount of time if there is no interrupt? They will get freed when packet 8 gets transmitted but there is no upper bound on when that will happen. Maybe I could create a tx skb cleanup timer that I kickoff in hard_start_xmit(). Every call to hard_start_xmit would reset the timer. I could try this for a future patch. Not sure if the extra code would cost me more than I get back in savings. > > I did see a significant boost to tx performance by optimizing start_xmit: > > more > > than double pps in pktgen. > > 148Kpps on a slow piece of hardware aint bad - Good Stuff. I wonder how > much CPU is being abused. > > If you wanna go one extra mile (separate future patch): get rid of that > tx lock and use netif_tx_lock on the interupt path. Look at some sane > driver like tg3 for reference. > Cool. I'll check out the tg3. - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
