On Mon, 16 Oct 2006 20:53:20 -0400 (EDT) John Heffner <[EMAIL PROTECTED]> wrote:
> The original message didn't show up on the list. I'm assuming it's > because the filters didn't like the attached postscript. I posted PDFs of > the figures on the web: > > http://www.psc.edu/~jheffner/tmp/a.pdf > http://www.psc.edu/~jheffner/tmp/b.pdf > http://www.psc.edu/~jheffner/tmp/c.pdf > > -John > > > ---------- Forwarded message ---------- > Date: Mon, 16 Oct 2006 15:55:53 -0400 (EDT) > From: John Heffner <[EMAIL PROTECTED]> > To: David Miller <[EMAIL PROTECTED]> > Cc: netdev <netdev@vger.kernel.org> > Subject: [PATCH] Bound TSO defer time > > This patch limits the amount of time you will defer sending a TSO segment > to less than two clock ticks, or the time between two acks, whichever is > longer. > > On slow links, deferring causes significant bursts. See attached plots, > which show RTT through a 1 Mbps link with a 100 ms RTT and ~100 ms queue > for (a) non-TSO, (b) currnet TSO, and (c) patched TSO. This burstiness > causes significant jitter, tends to overflow queues early (bad for short > queues), and makes delay-based congestion control more difficult. > > Deferring by a couple clock ticks I believe will have a relatively small > impact on performance. > > > Signed-off-by: John Heffner <[EMAIL PROTECTED]> Okay, but doing any timing on clock ticks makes the behavior dependent on the value of HZ which doesn't seem desirable. Should this be based on RTT or a real-time values? - 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
