Date: Wed, 9 Jul 2003 14:00:25 -0700 (PDT) From: Julian Elischer <julian@elischer.org> To: Kenneth Culver <culverk@yumyumyum.org> Cc: John Polstra <jdp@polstra.com> Subject: Re: wierd dsl performance with -CURRENT Message-ID: <Pine.BSF.4.21.0307091353440.22588-100000@InterJet.elischer.org> In-Reply-To: <20030709164151.A5579@alpha.yumyumyum.org>
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On Wed, 9 Jul 2003, Kenneth Culver wrote: > > Can you do a > > 'netstat -s -p tcp >> tcpstats' before and after the transfer? > > > > This should tell us if there were retransmits etc. It could be a > > difference in minimum rtt values or a congestion issue that results in > > timeout for our stack but some other recovery mechanism with other stacks. > > > > Here is the output of the netstat before and after transferring "kern.flp" > for FreeBSD 5.1: > > tcp: [...] > 35600 packets received [...] > 1220 out-of-order packets (1657153 bytes) > > This is after: > > tcp: [...] > 36688 packets received > 1298 out-of-order packets (1770089 bytes) This is the only thing that is of any interest.. and it could only really be if the etherent driver was re-ordering them.. possibly FreeBSD 5 might react more to out-of-order packets.. capture a download with tcpdump and save it (ascii version) to a file using the -ttt option to get relative timestamps.. look of any large values in the timestamps and see if there is anything before that indicates a lost packet or a re-ordered one or something (or a retransmitted ack) The key is to find the gap in the arriving packets and figure out what caused it.. > > Thanks... > > Could this be something my ISP did that causes a problem for FreeBSD and > not the other OS's? > > Ken >
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