X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fnics%2Fixgbe.rst;h=3dc6b004dff592786353c41e088ccf2238ece12d;hb=53fa8cc0d56d0f7e700fdcddfb4fa45c8d2b428d;hp=62cc0aab55552c1705320714e467c41c7b1278f3;hpb=7c574623baddfb8fa76a7435c0809a9119b8d485;p=dpdk.git

diff --git a/doc/guides/nics/ixgbe.rst b/doc/guides/nics/ixgbe.rst
index 62cc0aab55..3dc6b004df 100644
--- a/doc/guides/nics/ixgbe.rst
+++ b/doc/guides/nics/ixgbe.rst
@@ -95,7 +95,7 @@ Other features are supported using optional MACRO configuration. They include:
 
 *   HW extend dual VLAN
 
-*   Enabled by RX_OLFLAGS (RTE_IXGBE_RX_OLFLAGS_DISABLE=n)
+*   Enabled by RX_OLFLAGS (RTE_IXGBE_RX_OLFLAGS_ENABLE=y)
 
 
 To guarantee the constraint, configuration flags in dev_conf.rxmode will be checked:
@@ -154,13 +154,13 @@ Sample Application Notes
 testpmd
 ^^^^^^^
 
-By default, using CONFIG_RTE_IXGBE_RX_OLFLAGS_DISABLE=n:
+By default, using CONFIG_RTE_IXGBE_RX_OLFLAGS_ENABLE=y:
 
 .. code-block:: console
 
     ./x86_64-native-linuxapp-gcc/app/testpmd -c 300 -n 4 -- -i --burst=32 --rxfreet=32 --mbcache=250 --txpt=32 --rxht=8 --rxwt=0 --txfreet=32 --txrst=32 --txqflags=0xf01
 
-When CONFIG_RTE_IXGBE_RX_OLFLAGS_DISABLE=y, better performance can be achieved:
+When CONFIG_RTE_IXGBE_RX_OLFLAGS_ENABLE=n, better performance can be achieved:
 
 .. code-block:: console
 
@@ -178,3 +178,49 @@ load_balancer
 
 As in the case of l3fwd, set configure port_conf.rxmode.hw_ip_checksum=0 to enable vPMD.
 In addition, for improved performance, use -bsz "(32,32),(64,64),(32,32)" in load_balancer to avoid using the default burst size of 144.
+
+
+Malicious Driver Detection not Supported
+----------------------------------------
+
+The Intel x550 series NICs support a feature called MDD (Malicious
+Driver Detection) which checks the behavior of the VF driver.
+If this feature is enabled, the VF must use the advanced context descriptor
+correctly and set the CC (Check Context) bit.
+DPDK PF doesn't support MDD, but kernel PF does. We may hit problem in this
+scenario kernel PF + DPDK VF. If user enables MDD in kernel PF, DPDK VF will
+not work. Because kernel PF thinks the VF is malicious. But actually it's not.
+The only reason is the VF doesn't act as MDD required.
+There's significant performance impact to support MDD. DPDK should check if
+the advanced context descriptor should be set and set it. And DPDK has to ask
+the info about the header length from the upper layer, because parsing the
+packet itself is not acceptable. So, it's too expensive to support MDD.
+When using kernel PF + DPDK VF on x550, please make sure using the kernel
+driver that disables MDD or can disable MDD. (Some kernel driver can use
+this CLI 'insmod ixgbe.ko MDD=0,0' to disable MDD. Some kernel driver disables
+it by default.)
+
+
+Statistics
+----------
+
+The statistics of ixgbe hardware must be polled regularly in order for it to
+remain consistent. Running a DPDK application without polling the statistics will
+cause registers on hardware to count to the maximum value, and "stick" at
+that value.
+
+In order to avoid statistic registers every reaching the maximum value,
+read the statistics from the hardware using ``rte_eth_stats_get()`` or
+``rte_eth_xstats_get()``.
+
+The maximum time between statistics polls that ensures consistent results can
+be calculated as follows:
+
+.. code-block:: c
+
+  max_read_interval = UINT_MAX / max_packets_per_second
+  max_read_interval = 4294967295 / 14880952
+  max_read_interval = 288.6218096127183 (seconds)
+  max_read_interval = ~4 mins 48 sec.
+
+In order to ensure valid results, it is recommended to poll every 4 minutes.