Date: Mon, 21 Apr 2003 10:24:59 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: bj@dc.luth.se Cc: "Jin Guojun \[NCS\]" <j_guojun@lbl.gov> Subject: Re: patch for test (Was: tcp_output starving -- is due to mbuf get delay?) Message-ID: <3EA4296B.ACCD9AC8@mindspring.com> References: <200304210827.h3L8Rx2F032265@dc.luth.se>
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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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