Red Hat Bugzilla – Bug 503215
igb: dropping rx packets
Last modified: 2014-06-29 19:01:17 EDT
Description of problem:
When assigning igb device directly to KVM guest, netperf tx (from guest to external host) drops well below line rate (like 200Mb/s).
Version-Release number of selected component (if applicable):
RHEL 5.4 beta-ish (i.e. 2.6.18-150)
Steps to Reproduce:
1. assign igb device to guest
2. generate high tx traffic rate from guest to external host
3. observe poor throughput
throughput for tcp stream netperf test falls to ~200Mb/s
Seems to be dropping large numbers of RX packets. Also the RX interrupt rate is low. Suspect some kind of NAPI problem.
Created attachment 345941 [details]
Patch that I will post after getting feedback from Chris that the igbvf stuff is better/not worse than before.
This request was evaluated by Red Hat Product Management for inclusion in a Red
Hat Enterprise Linux maintenance release. Product Management has requested
further review of this request by Red Hat Engineering, for potential
inclusion in a Red Hat Enterprise Linux Update release for currently deployed
products. This request is not yet committed for inclusion in an Update
You can download this test kernel from http://people.redhat.com/dzickus/el5
Please do NOT transition this bugzilla state to VERIFIED until our QE team
has sent specific instructions indicating when to do so. However feel free
to provide a comment indicating that this fix has been verified.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on therefore solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.