On Fri, Feb 18, 2011 at 07:44:30PM -0800, Nathaniel Smith wrote: > On Fri, Feb 18, 2011 at 1:21 PM, John W. Linville > <linville@xxxxxxxxxxxxx> wrote: > > + /* grab timestamp info for buffer control estimates */ > > + tserv = ktime_sub(ktime_get(), skb->tstamp); > [...] > > + ewma_add(&sta->sdata->qdata[q].tserv_ns_avg, > > + ktime_to_ns(tserv)); > > I think you're still measuring how long it takes one packet to get > from the end of the queue to the beginning, rather than measuring how > long it takes each packet to go out? Yes, I am measuring how long the driver+device takes to release each skb back to me (using that as a proxy for how long it takes to get the fragment to the next hop). Actually, FWIW I'm only measuring that time for those skb's that result in a tx status report. I tried to see how your measurement would be useful, but I just don't see how the number of frames ahead of me in the queue is relevant to the measured link latency? I mean, I realize that having more packets ahead of me in the queue is likely to increase the latency for this frame, but I don't understand why I should use that information to discount the measured latency...? John -- John W. Linville Someday the world will need a hero, and you linville@xxxxxxxxxxxxx might be all we have. Be ready. -- 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
