On Thu, 2005-08-11 at 16:15 -0700, David S. Miller wrote: > From: "Leonid Grossman" <[EMAIL PROTECTED]> > Date: Thu, 11 Aug 2005 19:05:22 -0400 > > > Basically, it looks like with SuperTSO most of the traffic in our tests > > comes down to the driver with mss 0 (TSO is mostly "off"). > > With the original TSO, is was always "on" (see below). > > Could you describe how SuperTSO algorithm for switching TSO "on" and > > "off" works, it seems to be fairly complex for us to mess with? For a > > fast network with extremely low error rate, I'd expect TSO to be on. > > We build packets as large as the user gives us in sendmsg(), > then when ACK's come in openning up the window we either > send as much as we can at that moment, or we defer to wait > for more space so we can build larger TSO frames.
But even with new TSO schema, this logic can not send more than MAX_SKB_FRAGS which at best case ~60K. With old TSO schema. I thought with SuperTSO we could send >> than 60K. And than it could be very beneficial for us on some platforms where DMA setup is very cheap, since we could xmit up to 256 pages at once. > The logic for that decision is in: > > net/ipv4/tcp_output.c:tcp_tso_should_defer() ok, I'll take a look. > Keep also in mind that if there is packet loss, TSO is disabled > completely. I'll double check that too. Thanks! Dima - 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
