Date: Mon, 8 Sep 2014 22:12:14 -0700 From: Adrian Chadd <adrian@freebsd.org> To: FreeBSD Net <freebsd-net@freebsd.org>, Jack F Vogel <jfv@freebsd.org>, "Joyner, Eric" <eric.joyner@intel.com> Subject: [igb] add DROP_EN to each RX queue config if TX flow control is disabled Message-ID: <CAJ-Vmok6aSE=ZFZcrBCZUTdHTXosE2eAzG%2Bxkhwn=XM7c7P3Pg@mail.gmail.com>
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Hi, This patch enables the DROP_EN flag to each RX queue if TX flow control is disabled. It (mostly) mirrors what the ixgbe driver does. This prevents a single full RX ring from stalling the rest of the RX rings. How's it look? (indenting and such aside, thanks google.) -a Index: sys/dev/e1000/if_igb.c =================================================================== --- sys/dev/e1000/if_igb.c (revision 271290) +++ sys/dev/e1000/if_igb.c (working copy) @@ -4712,6 +4712,18 @@ rctl |= E1000_RCTL_SZ_2048; } + /* + * If TX flow control is disabled and there's >1 queue defined, + * enable DROP. + * + * This drops frames rather than hanging the RX MAC for all queues. + */ + if ((adapter->num_queues > 1) && + (adapter->fc == e1000_fc_none || + adapter->fc == e1000_fc_rx_pause)) { + srrctl |= E1000_SRRCTL_DROP_EN; + } + /* Setup the Base and Length of the Rx Descriptor Rings */ for (int i = 0; i < adapter->num_queues; i++, rxr++) { u64 bus_addr = rxr->rxdma.dma_paddr; @@ -6255,6 +6267,7 @@ adapter->hw.fc.current_mode = adapter->hw.fc.requested_mode; e1000_force_mac_fc(&adapter->hw); + /* XXX TODO: update DROP_EN on each RX queue if appropriate */ return (error); }
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