Date: Fri, 07 Mar 2003 11:02:23 -0800 From: Terry Lambert <tlambert2@mindspring.com> To: Petri Helenius <pete@he.iki.fi> Cc: Bosko Milekic <bmilekic@unixdaemons.com>, freebsd-current@FreeBSD.ORG Subject: Re: mbuf cache Message-ID: <3E68ECBF.E7648DE8@mindspring.com> References: <0ded01c2e295$cbef0940$932a40c1@PHE> <20030304164449.A10136@unixdaemons.com> <0e1b01c2e29c$d1fefdc0$932a40c1@PHE> <20030304173809.A10373@unixdaemons.com> <0e2b01c2e2a3$96fd3b40$932a40c1@PHE> <20030304182133.A10561@unixdaemons.com> <0e3701c2e2a7$aaa2b180$932a40c1@PHE> <20030304190851.A10853@unixdaemons.com> <001201c2e2ee$54eedfb0$932a40c1@PHE> <20030307093736.A18611@unixdaemons.com> <008101c2e4ba$53d875a0$932a40c1@PHE>
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Petri Helenius wrote: > > There's probably a tightloop of frees going on somewhere. It's tough > > for me to analyze this as I cannot reproduce it. Have you tried > > running your tests over loopback to see if the same thing happens? > > What is the definition of "tightloop"? The received packet mbufs are freed > when the packets get processed/discarded which happens once for > a packet. The received packet rate is 50000-150000 packets per second. > > > > If so, and it does, can you please explain how to exactly replicate > > the test? > > Mirror a port with ~300-800Mbps of IP traffic to an em port. Just enable > promisc and monitor so it drops the packets after interrupt processing. > The overhead beyond that is neglible compared to mb_free. Ah. You are receiver livelocked. Try enabling polling; it will help up to the first stall barrier (NETISR not getting a chance to run protocol processing to completion because of interrupt overhead); there are two other stall barriers after that, and another in user space is possible depending on whether the application layer is request/response. -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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