
Issue 11
© Solarflare Communications 2014
320
Solarflare Server Adapter
User Guide
7.6 Performance Tuning
The guest drivers have been tuned for optimized bandwidth and CPU utilization with a variety of high
bandwidth streaming tests. Some applications may perform better by changing the default values.
describes the tuning parameters and suggests values for streaming and latency dominated
applications.
To modify these settings:
1. Edit
/etc/modprobe.conf
, inserting a line like this:
options xnap rx_irq_mod_usec=<value> rx_ring=<value>
2. Reload the xnap driver
# modprobe -r xnap
# modprobe xnap
Performance Configuration
• Equipment Configuration
Performance tests were conducted between two (back to back) Dell PowerEdge C6100: 4 x Xeon
X5600, 48G RAM. Host and Guest are configured on each machine.
• Host
- Host OS: RHEL 6.2 64 bit.
- The irqbalance service is stopped.
• Guest
- The guest VM was running RHEL6.1 64bit.
- The irqbalance service was stopped in the guest VM.
- Benchmarking tool: Netperf.
Table 82: Tuning Parameters
Parameter
Linux
Streaming
Latency
Receive ring size
rx_ring
Default
Default
Interrupt Moderation
rx_irq_mod_usecs
Default
0