Red Hat Bugzilla – Bug 599331
e1000 and e1000e driver behaviour differences [rhel-5.5.z]
Last modified: 2010-12-07 18:24:31 EST
This bug has been copied from bug #586416 and has been proposed
to be backported to 5.5 z-stream (EUS).
*** This bug has been marked as a duplicate of bug 599332 ***
Technical note added. If any revisions are required, please edit the "Technical Notes" field
accordingly. All revisions will be proofread by the Engineering Content Services team.
The e1000 and e1000e drivers for Intel PRO/1000 network devices were updated with an enhanced algorithm for adaptive interrupt modulation in the Red Hat Enterprise Linux 5.1 release. When InterruptThrottleRate was set to "1" (thus enabling the new adaptive mode), certain traffic patterns could have caused high CPU usage. This update provides a way to set InterruptThrottleRate to "4", which switches the mode back to the simpler and non-adaptive algorithm. Doing so may decrease CPU usage by the e1000 and e1000e drivers depending on traffic patterns.
Note: you can change the InterruptThrottleRate setting using the ethtool utility by running the following command:
ethtool -C ethX rx-usecs 4