Re: svn commit: r189117 - head/sys/dev/bce

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From
Tom Judge <tom@tomjudge.com>
Date
6 Aug 2009 16:24:03
Subject
Re: svn commit: r189117 - head/sys/dev/bce
Message-ID
4A7AFFC4.5050607@tomjudge.com


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Hi,

Stanislav Sedov wrote:
> On Fri, 27 Feb 2009 19:25:06 +0000 (UTC)
> David Christensen <davidch@FreeBSD.org> mentioned:
>
>
>> Author: davidch
>> Date: Fri Feb 27 19:25:06 2009
>> New Revision: 189117
>> URL: http://svn.freebsd.org/changeset/base/189117
>>
>> Log:
>> - Update copyright to 2009.
>> - Only enable split header operation when ZERO_COPY_SOCKETS is enabled in
>> the kernel.
>>
>>
>
> Hi, David!
>
> It appears that this change leads to excessive memory fragmentation due to
> large number of 9k contiguous buffers allocations performed. I noticed
> that under the relatively high load this can quickly lead to inability to send
> any packets via bce(4) even on machines with high amount of memory (16 Gb).
> I've been running with this change backed out for a long time and I don't
> see any problems with this driver with last changes applied.
>
>

I can confirm that we are also seeing this problem on a number of Dell
PE2950 systems running the bce driver from 7.2, the bug is more
visible/producible on systems that are using Jumbo Frames (in our case 8Kb).

The symptoms of this are an increase in the requests for jumbo clusters
denied counter at 9k, and then random network stalls which sometimes
recover on there own and others require a reboot.

We have backed this change and so far it seems to have fixed the issue.

Regards

Tom Judge

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