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From: Rick Jones <rick.jones2@hp.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: netdev@vger.kernel.org, bugme-daemon@bugzilla.kernel.org,
	arno@heho.snv.jussieu.fr, Ayaz Abdulla <aabdulla@nvidia.com>
Subject: Re: [Bugme-new] [Bug 11752] New: Extremely low netperf UDP_RR	throughput for nvidia MCP65
Date: Thu, 16 Oct 2008 14:07:38 -0700	[thread overview]
Message-ID: <48F7AD1A.7050309@hp.com> (raw)
In-Reply-To: <20081016134920.1492cdcc.akpm@linux-foundation.org>

Andrew Morton wrote:
> (switched to email.  Please respond via emailed reply-to-all, not via the
> bugzilla web interface).
> 
> On Mon, 13 Oct 2008 13:41:19 -0700 (PDT)
> bugme-daemon@bugzilla.kernel.org wrote:
> 
> 
>>http://bugzilla.kernel.org/show_bug.cgi?id=11752
>>
>>           Summary: Extremely low netperf UDP_RR throughput for nvidia MCP65
>>           Product: Drivers
>>           Version: 2.5
>>     KernelVersion: from F10-Beta-x86_64-Live-KDE.iso
>>          Platform: All
>>        OS/Version: Linux
>>              Tree: Mainline
>>            Status: NEW
>>          Severity: normal
>>          Priority: P1
>>         Component: Network
>>        AssignedTo: jgarzik@pobox.com
>>        ReportedBy: arno@heho.snv.jussieu.fr
>>
>>
>>Latest working kernel version: -
>>Earliest failing kernel version:
>>Distribution: F10-Beta-x86_64
>>Hardware Environment: HP Pavillon dv6820ef
>>Software Environment:
>>Problem Description: when running at 1Gbps netperf shows good performance for
>>TCP_STREAM and UDP_STREAM tests, but extremely bad performance for UDP_RR test
>>(less then 1 ping-pong a second whereas at 100Mbps performance easily reaches
>>10-20K a second)
>>
>>A friend figured out that it looks like small packets at 1Gbps are dropped
>>as being falsely considered crc-errored.

Given how netperf UDP_RR has _no_ recovery from lost datagrams, it makes 
sense that performance on that test would be very low - the first lost 
datagram the transactions come to a screeching halt until the 
end-of-test timer expires.

Are netstat stats showing retransmissions during a TCP_STREAM test?  How 
about a TCP_RR test?  TCP_RR might be low too, it just wouldn't 
necessarily be as low since TCP will get things started again after a 
loss.   UDP_STREAM would just go blasting along without a care in the 
world...

rick jones

  reply	other threads:[~2008-10-16 21:07 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <bug-11752-10286@http.bugzilla.kernel.org/>
2008-10-16 20:49 ` [Bugme-new] [Bug 11752] New: Extremely low netperf UDP_RR throughput for nvidia MCP65 Andrew Morton
2008-10-16 21:07   ` Rick Jones [this message]
2008-10-17 14:28     ` Arno J. Klaassen
2008-10-17 20:49     ` Arno J. Klaassen
2008-10-17 21:05       ` Rick Jones
2008-10-18 11:36         ` Arno J. Klaassen
2008-10-20 17:41           ` Rick Jones
2008-10-31 13:07             ` Arno J. Klaassen
2008-12-11 20:53             ` Arno J. Klaassen

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