Bug 697625

Summary: Increased UDP/IPv6 loss on Intel 82599EB 10-Gigabit NIC
Product: Red Hat Enterprise Linux 6 Reporter: Adam Okuliar <aokuliar>
Component: kernelAssignee: Andy Gospodarek <agospoda>
Status: CLOSED INSUFFICIENT_DATA QA Contact: Red Hat Kernel QE team <kernel-qe>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 6.1CC: arozansk, peterm, syeghiay
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2011-08-16 20:35:49 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description Adam Okuliar 2011-04-18 18:51:18 UTC 
Description of problem:
rhel6.1 has 2 times higher UDP datagram loss when receiving 1400Bytes long datagrams over 10gig ethernet than rhel6.0

Version-Release number of selected component (if applicable):
2.6.32-131.0.1.el6.x86_64

How reproducible:
100%

Steps to Reproduce:
1.run /root/prepare_sys.py
2.run netperf -H 172.16.29.20 -t UDP_STREAM -- -m 1000

Socket  Message  Elapsed      Messages                
Size    Size     Time         Okay Errors   Throughput
bytes   bytes    secs            #      #   10^6bits/sec

124928    1000   10.00     5026535      0    4021.23
124928           10.00     2139250           1711.40

  
Actual results:
RHEL 6.1

Expected results:
datagram loss decreased to rhel6.0 levels

Additional info:

Please see: http://download.englab.brq.redhat.com/perf-results//netperf/RHEL61-20110413/#u6_fd29--10_to_fd29--20_tp
on this plot is shown local send throughput of rhel6.0 and 6.1. Both systems sends almost same amount of data.

On this plot http://download.englab.brq.redhat.com/perf-results//netperf/RHEL61-20110413/#u6_fd29--10_to_fd29--20_rtp received traffic is shown. Rhel6.1 receives significantly smaller amount of data.

On this plot http://download.englab.brq.redhat.com/perf-results//netperf/RHEL61-20110413/#u6_fd29--10_to_fd29--20_lt is shown how much network traffic is lost. It is clear that on rhel6.1 amount of lost traffic is much higher.
Comment 2 Andy Gospodarek 2011-04-25 19:22:59 UTC 
I presume the 82599 interfaces were the only ones that saw this drop?

I would be curious to know how the RHEL6.0 throughput compares to 2.6.32-71.27.1.el6 or later.  There are changes in RHEL6.1 and 2.6.32-71.27.1.el6 that fix an erratum, but likely impact performance.

Would you be able to run a similar test with RHEL6.0.z kernel 2.6.32-71.27.1.el6 or later to help verify?