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Date: Sat, 09 Feb 2008 20:36:28 -0200
From: =?ISO-8859-1?Q?Daniel_Dias_Gon=E7alves?= <daniel@dgnetwork.com.br>
Organization: DGNET Network Solutions
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Subject: DEVICE_POLLING IF_EM CPU usage
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Hi,

I activated polling in 8 interfaces em0... em7 (ifconfig em* polling) to 
carry through performance tests, when activating, it had a significant 
reduction of CPU usage, load average measured of "0,50, 0,69, 0,52" for 
"0,43, 0,39, 0,21" and the CPU usage (SNMP Graphic) measured of 35% for 
5%. Passed some hours I disactivated polling (ifconfig em* - polling) 
and CPU usage continues low.
Somebody could explain this to me?

Some information:

FreeBSD 6.3-RELEASE

CPU: Intel(R) Xeon(TM) CPU 3.20GHz (3200.13-MHz 686-class CPU)
 Logical CPUs per core: 2
FreeBSD/SMP: Multiprocessor System Detected: 2 CPUs
SMP: AP CPU #1 Launched!

Interfaces if_em:
   vendor     = 'Intel Corporation'
   device     = '82546EB Dual Port Gigabit Ethernet Controller'


Thanks.

Daniel