Date: Wed, 6 Jul 2011 14:28:19 -0700 From: "David Christensen" <davidch@broadcom.com> To: "pyunyh@gmail.com" <pyunyh@gmail.com>, "Charles Sprickman" <spork@bway.net> Cc: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org>, David Christensen <davidch@freebsd.org> Subject: RE: bce packet loss Message-ID: <5D267A3F22FD854F8F48B3D2B523819385C32D9115@IRVEXCHCCR01.corp.ad.broadcom.com> In-Reply-To: <20110706201509.GA5559@michelle.cdnetworks.com> References: <alpine.OSX.2.00.1107042113000.2407@freemac> <20110706201509.GA5559@michelle.cdnetworks.com>
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> You had 282 RX buffer shortages and these frames were dropped. This > may explain why you see occasional packet loss. 'netstat -m' will > show which size of cluster allocation were failed. > However it seems you have 0 com_no_buffers which indicates > controller was able to receive all packets destined for this host. > You may host lost some packets(i.e. non-zero mbuf_alloc_failed_count) > but your controller and system was still responsive to the network > traffic. >=20 > Data sheet says IfHCInBadOctets indicates number of octets received > on the interface, including framing characters for packets that > were dropped in the MAC for any reason.=20 The IfHcInBadOctets counter says the controller received X bytes=20 that were bad on the wire (collisions, FCS errors, etc.). A value of 539,369 would equal about 355 frames @ 1518 bytes per frame. How bad that is really depends on the amount of time the server was running. The minimum bit-error rate (BER) for 1000Base-T is=20 10^-12, so running at line rate you'd expect to see an error very 1000 seconds according to the following link: http://de.brand-rex.com/LinkClick.aspx?fileticket=3DTFxnnLPedAg%3D&tabid=3D= 1956&mid=3D5686 Most vendors design to greater than 10^-12 and you're probably not running at line rate all the time so you should see fewer errors. In my testing I can go for days without seeing any errors, but if you run long enough or have marginal interconnects/cabling the=20 error rate will rise. Dave
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