Date: Thu, 10 Apr 2003 04:41:32 -0500 (CDT) From: Mike Silbersack <silby@silby.com> To: Borje Josefsson <bj@dc.luth.se> Cc: David Gilbert <dgilbert@velocet.ca> Subject: Re: tcp_output starving -- is due to mbuf get delay? Message-ID: <20030410043827.A936@odysseus.silby.com> In-Reply-To: <20030410171640.C44793B2@porter.dc.luth.se> References: <20030410171640.C44793B2@porter.dc.luth.se>
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On Thu, 10 Apr 2003, Borje Josefsson wrote: > > > Have you tried running kernel profiling yet? It would be interesting to > > > see which functions are using up the largest amount of time. > > Could do that if I knew how... Not before the weekend though, right now > I'm at the longue at the airport... I believe that the manpages regarding how to set it up were pretty useful, it didn't take me long to get it operational last time I tried. However, that was a while ago, so I can't give you any helpful tips. > If everything is OK (which it apparently isn't), top will show free CPU, > and netstat should show a *very* steady packet flow (around 90kpps if You > have MTU 1500). Any packet loss is fatal for this speed, so if there is a > way (as indicated by Mike above) to not restarting with windowsize from > scratch that will make recovery much better. Well, the packet loss I pointed out would be due to the ifqueue overflowing, which could concieveably happen even if the actual network wasn't congested. I don't have the equipment to create such a situation, but it sounds like you might, in which case adding a debug printf or a counter to see if it's happening might be advantageous. Mike "Silby" Silbersack
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