Date: Wed, 23 Aug 2006 20:16:49 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: David Christensen <davidch@broadcom.com> Cc: brad@openbsd.org, oleg@FreeBSD.org, net@FreeBSD.org Subject: bge(4) one packet wedge Message-ID: <20060823161649.GE76666@cell.sick.ru>
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Colleagues, I've faced a problem in bge(4) when a single packet is in the RX ring, but it isn't noticed by the driver. A reception of a packet triggers interrupt and both packets are processed - an old one and the new one. To reproduce the problem you need to run netperf (from ports collection): netserver on another host (10.0.0.1) and netperf on the host, where tested bge(4) is installed - 10.0.0.2. No traffic except netperf's should flow through this NIC, or the problem won't be reproduced! So, I run netperf client and simultaneously tcpdump on the another host. After few seconds there is a wedge. The last packet seen on 10.0.0.1 is the packet sent by 10.0.0.1 to 10.0.0.2. However it isn't seen on 10.0.0.2. Ok, let's look at the receive ring: (kgdb) p $sc->bge_rx_saved_considx $14 = 51 (kgdb) p $sc->bge_ldata.bge_status_block->bge_idx[0].bge_rx_prod_idx $15 = 51 Looks like there is nothing to process. However, if I run 'ping -c 1 10.0.0.2' I will get an interrupt and read two packets: first the old packet, and then recently sent ping. -- Totus tuus, Glebius. GLEBIUS-RIPN GLEB-RIPE
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