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Date:      Tue, 30 Jan 2007 13:58:17 -0500
From:      Mike Tancsa <mike@sentex.net>
To:        "Jack Vogel" <jfvogel@gmail.com>
Cc:        freebsd-stable@freebsd.org
Subject:   Re: Intel EM tuning (PT1000 adaptors)
Message-ID:  <200701301859.l0UIx9qK002719@lava.sentex.ca>
In-Reply-To: <2a41acea0701300930u4f920b95n61d20972c14576a9@mail.gmail.co m>
References:  <200701301719.l0UHJ1Kk002345@lava.sentex.ca> <2a41acea0701300930u4f920b95n61d20972c14576a9@mail.gmail.com>

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At 12:30 PM 1/30/2007, Jack Vogel wrote:

>Performance tuning is not something that I have yet had time to focus
>on, our Linux team is able to do a lot more of that. Just at a glance,
>try increasing your mbuf pool size and the number of receive descriptors
>for a start. Oh, and try increasing your processing limit to 200 and see
>what effect that has.

Hi, thanks for the info. What is the processing_limit limit, and 
apart from crashing the box, how do I know if I set it too high ? ;-)

I am not sure which mbuf setting you mean ? From netstat -m, I dont 
seem to be hitting any max values

# netstat -m
838/2237/3075 mbufs in use (current/cache/total)
836/578/1414/25600 mbuf clusters in use (current/cache/total/max)
836/572 mbuf+clusters out of packet secondary zone in use (current/cache)
0/0/0/0 4k (page size) jumbo clusters in use (current/cache/total/max)
0/0/0/0 9k jumbo clusters in use (current/cache/total/max)
0/0/0/0 16k jumbo clusters in use (current/cache/total/max)
1881K/1715K/3596K bytes allocated to network (current/cache/total)
0/0/0 requests for mbufs denied (mbufs/clusters/mbuf+clusters)
0/0/0 requests for jumbo clusters denied (4k/9k/16k)
0/5/6656 sfbufs in use (current/peak/max)
0 requests for sfbufs denied
0 requests for sfbufs delayed
0 requests for I/O initiated by sendfile
0 calls to protocol drain routines

As for hw.em.rxd, how do I know what this chip can handle ? It says 
the current default is 256, but I dont know what I can set that too, 
based on this adaptor ?

WRT,     hw.em.rx_int_delay
              This value delays the generation of receive interrupts in units
              of 1.024 microseconds.  The default value is 0, since adapters
              may hang with this feature being enabled.

Do you know which adaptors have this issue ?


Also, for
     hw.em.rx_abs_int_delay
              If hw.em.rx_int_delay is non-zero, this tunable limits the maxi-
              mum delay in which a receive interrupt is generated.

I take it this is for interrupt moderation ? Am I right in thinking 
that if my rx buffers are filling, the box is not processing 
interrupts fast enough so I should move this value closer to zero 
?  How do I find what the current value is ?

Thanks for any pointers you can provide.


         ---Mike





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