Re: [PATCH] netif_rx: receive path optimization
From: jamal <hidden>
Date: 2005-03-31 03:16:42
On Wed, 2005-03-30 at 18:53, Stephen Hemminger wrote:
How about percentages instead of multiple sysctl values? Or some relationship of max_queue and max_backlog. success qlen < max_backlog low qlen > max_backlog medium qlen > max_queue/2 high qlen > max_queue - max_backlog drop qlen > max_queue
Well, you still need the moving window average computation to detect the second order effect (of an oncoming tsunami). Unless i misunderstood - you are suggesting looking at instantenous values
Also, RAND_LIE (dead code) is kind of confusing because I expected it to be a receive version of Random Drop, but it really just lies back to the caller (and keeps the packet).
If you have drivers which look at the feedback value - then they will back off. We dont drop but we do hope that by telling the driver to back off that it listens to us. Clearly if you have drivers that dont listen then its like running UDP on a wire with everyone trying to shove packets. For some numbers and experiments on this stuff circa 1999/2000 look at: http://robur.slu.se/Linux/net-development/jamal/FF-html/ You may find at least one entertaining: http://robur.slu.se/Linux/net-development/jamal/FF-html/img20.htm cheers, jamal