Date: Wed, 08 Jan 2014 00:42:24 +0000 From: Joe Holden <lists@rewt.org.uk> To: Garrett Wollman <wollman@bimajority.org>, freebsd-net@freebsd.org Subject: Re: ETHER_MAX_LEN_JUMBO Message-ID: <52CC9EF0.5010504@rewt.org.uk> In-Reply-To: <21196.29430.733181.353677@hergotha.csail.mit.edu> References: <21196.29430.733181.353677@hergotha.csail.mit.edu>
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16k frames are available on commidity intel cards so perhaps a bump to 16k should be enough for the foreseeable future, although saying that there is nothing to stop another big leap in frame sizes. We should probably be ahead of the curve here, rather than playing catch up with vendors. Would it be possible to limit the max size by looking at drivers in the tree at compile-time, perhaps have them declare the max frame size the supported hardware can handle? On 07/01/2014 21:34, Garrett Wollman wrote: > In <net/ethernet.h>, the constant ETHER_MAX_LEN_JUMBO is set to 9018. > According to svn, this was added by sam back in 2002, and now seems a > bit low. Our maximum MTU at work has always been 9120 (implying 9138 > for ETHER_MAX_LEN_JUMBO), and we have hardware in production now that > defaults to 12000. The ixgbe driver doesn't use this constant, bu > the cxgbe driver does. Does anyone know a reason I should *not* > increase it to a more reasonable level? (9216 would be my choice if > we wanted to stick with values in the 9k range.) > > -GAWollman > > _______________________________________________ > freebsd-net@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-net > To unsubscribe, send any mail to "freebsd-net-unsubscribe@freebsd.org" >
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