patch for test (Was: tcp_output starving -- is due to mbuf get
delay?)
Terry Lambert
tlambert2 at mindspring.com
Mon Apr 21 10:26:28 PDT 2003
Borje Josefsson wrote:
[ ... Jin Guojun's TCP output patch for high bandwidth delay product ... ]
> This patch definitively works, and gives much higher PPS (32000 instead of
> 19000). This is on a low-end system (PIII 900MHz with 33MHz bus), I'll
> test one of my larger systems later today.
>
> One question though - is there any way of having the code being more
> "aggressive"? As You see, in the netstat output below, it takes ~35
> seconds(!) before reaching full speed. On NetBSD I reach maxPPS almost
> immediately. Even if we now (with Your patch) can utilize the hardware
> much more, it only helps if You have connections that lasts for a very
> long time, so that the "ramping" time is not significant.
You can get immediate relief by porting this code instead of
using the patch:
http://www.psc.edu/networking/tcp.html#psc
It is for NetBSD 1.3.2, and includes a SACK, Rate Halving,
auto-tuning, and explicit congestion notification:
Description:
http://www.psc.edu/networking/rate_halving.html
Direct link to the code:
http://www.psc.edu/networking/ftp/tools/netbsd132_rh_10.tgz
Also included is a FACK implementation.
-- Terry
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