Product specifications

QLogic OFED+ Host Software Page 11 of 20
5.5 Performance Tuning
Tuning for verbs performance can be accomplished by making the following changes.
5.5.1 Intel CPU Systems (in general)
Set the BIOS using the following procedure:
1. Set PCIe parameter MaxPayLoad = 256 bytes
2. Set PCIe parameter MaxReadRequest = 4096 bytes
3. Disable all C-States.
4. Disable Intel Hyper-Threading technology
If the BIOS does not support the MaxPayLoad and MaxReadRequest settings, add the
following parameter to the /etc/modprobe.conf file’s options ib_qib line:
pcie_caps=0x51
Set the C-State to 0 where there is no BIOS support, by performing the following
procedure:
1. Add kernel boot option: processor.max_cstate=0
2. Reboot.
Turn off the specified daemons using the following commands:
/sbin/chkconfig irqbalance off
/sbin/chkconfig --level 12345 cpuspeed off (for RHEL or similar systems)
/sbin/chkconfig --level 12345 powersaved off (for SLES systems)
/sbin/chkconfig --level 12345 haldaemon off
Set init runlevel = 3
5.5.2 Intel CPU Systems (additions for Lustre/GPFS over verbs
RDMA)
One of the following parameters sets up the QLogic driver to accomplish these settings for
Lustre/GPFS over verbs RDMA. For single-port Host Channel Adapters, the line would look
like one of the following according to the core and CPU type of the node:
For 12-core, Intel Westmere, Xeon 56xx 6-core CPU, nodes:
options ib_qib singleport=1 pcie_caps=0x51 krcvqs=4 rcvhdrcnt=4096
For 8-core, Intel Nehalem, Xeon 55xx, nodes:
options ib_qib singleport=1 pcie_caps=0x51 krcvqs=8 rcvhdrcnt=4096