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);
}
help
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