User guide

NetXtreme II User Guide
September 2013
Broadcom Corporation
Page 154 Setting Values for Optional Properties Document INGSRVT78-CDUM100-R
dropless_fc
The dropless_fc parameter can be used to enable a complementary flow control mechanism on BCM57711/BCM57712
adapters. The default flow control mechanism is to send pause frames when the on-chip buffer (BRB) is reaching a certain
level of occupancy. This is a performance targeted flow control mechanism. On BCM57711/BCM57712 adapters, one can
enable another flow control mechanism to send pause frames, where one of the host buffers (when in RSS mode) are
exhausted.
This is a "zero packet drop" targeted flow control mechanism.
Set the dropless_fc parameter to 1 to enable the dropless flow control mechanism feature on all BCM57711/BCM57712
NetXtreme II adapters in the system.
insmod bnx2x.ko dropless_fc=1
or
modprobe bnx2x dropless_fc=1
disable_iscsi_ooo
The disable_iscsi_ooo parameter is to disable the allocation of the iSCSI TCP Out-of-Order (OOO) reception resources,
specifically for VMware for low-memory systems.
multi_mode
The optional parameter multi_mode is for use on systems that support multi-queue networking. Multi-queue networking on
the receive side depends only on MSI-X capability of the system, multi-queue networking on the transmit side is supported
only on kernels starting from 2.6.27. By default, multi_mode parameter is set to 1. Thus, on kernels up to 2.6.26, the driver
will allocate on the receive side one queue per-CPU and on the transmit side only one queue. On kernels starting from
2.6.27, the driver will allocate on both receive and transmit sides, one queue per-CPU. In any case, the number of allocated
queues will be limited by number of queues supported by hardware.
The multi_mode optional parameter can also be used to enable SAFC (Service Aware Flow Control) by differentiating the
traffic to up to 3 CoS (Class of Service) in the hardware according to the VLAN PRI value or according to the IP DSCP value
(least 3 bits).
num_queues
The optional parameter num_queues may be used to set the number of queues when multi_mode is set to 1 and interrupt
mode is MSI-X. If interrupt mode is different than MSI-X (see int_mode), the number of queues will be set to 1, discarding
the value of this parameter.
pri_map
The optional parameter pri_map is used to map the VLAN PRI value or the IP DSCP value to a different or same CoS in
the hardware. This 32-bit parameter is evaluated by the driver as an 8 value of 4 bits each. Each nibble sets the desired
hardware queue number for that priority. For example, set pri_map to 0x11110000 to map priority 0 to 3 to CoS 0 and map
priority 4 to 7 to CoS 1.
qs_per_cos