Chelsio Communications Chelsio T4, Инструкция по установке и эксплуатации

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Chapter II. Network (NIC/TOE)
Chelsio T5/T4 Unified Wire for Linux
Page 56
sysctl -w net.core.busy_read=<value>
sysctl -w net.core.busy_poll=<value>
Set the values of the above parameters to 50 for 100 or less connections; and 100 for more
than 100 connections.
4.3. Performance Tuning
Receiver Side Scaling (RSS)
Receiver Side Scaling enables the receiving network traffic to scale with the available number of
processors on a modern networked computer. RSS enables parallel receive processing and
dynamically bal
ances the load among multiple processors. Chelsio’s T5/T4 network controller
fully supports Receiver Side Scaling for IPv4 and IPv6.
This script first determines the number of CPUs on the system and then each receiving queue is
bound to an entry in the system interrupt table and assigned to a specific CPU. Thus, each
receiving queue interrupts a specific CPU through a specific interrupt now. For example, on a 4-
core system,
t4_perftune.sh gives the following output:
[root@host~]# t4_perftune.sh
Discovering Chelsio T4/T5 devices ...
Configuring Chelsio T4/T5 devices ...
Tuning eth7
IRQ table length 4
Writing 1 in /proc/irq/62/smp_affinity
Writing 2 in /proc/irq/63/smp_affinity
Writing 4 in /proc/irq/64/smp_affinity
Writing 8 in /proc/irq/65/smp_affinity
eth7 now up and tuned
...
Because there are 4 CPUs on the system, 4 entries of interrupts are assigned. For other T5/T4
network interfaces, you should see similar output message.
Now the receiving traffic is dynamically assigned to one of the system’s CPUs through a T5/T4
queue. This achieves a balanced usage among all the processors. This can be verified, for
example, by using the
iperf tool. First set up a server on the receiver host:
BUSY_POLL can also be enabled on a per-connection basis by making use of
SO_BUSY_POLL option in the socket application code. Refer socket man-page for
more details.
Note