Date: Sat, 13 Sep 2014 22:14:31 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Adrian Chadd <adrian@freebsd.org> Subject: Re: svn commit: r271504 - in head/sys: dev/oce dev/vmware/vmxnet3 dev/xen/netfront net netinet ofed/drivers/net/mlx4 Message-ID: <5414A5A7.9030108@selasky.org> In-Reply-To: <405398541.35874200.1410638660648.JavaMail.root@uoguelph.ca> References: <405398541.35874200.1410638660648.JavaMail.root@uoguelph.ca>
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On 09/13/14 22:04, Rick Macklem wrote: > Hans Petter Selasky wrote: >> On 09/13/14 18:54, Adrian Chadd wrote: >>> Hi, >>> >>> Just for the record: >>> >>> * I'm glad you're tackling the TSO config stuff; >>> * I'm not glad you're trying to pack it into a u_int rather than >>> creating a new structure and adding fields for it. >>> >>> I appreciate that you're trying to rush this in before 10.1, but >>> this >>> is exactly why things shouldn't be rushed in before release >>> deadlines. >>> :) >>> >>> I'd really like to see this be broken out as a structure and the >>> bit >>> shifting games for what really shouldn't be packed into a u_int >>> fixed. >>> Otherwise this is going to be deadweight that has to persist past >>> 11.0. >>> >> >> Hi Adrian, >> >> I can make that change for -current, making the new structure and >> such. >> This change was intended for 10 where there is only one u_int for >> this >> information. Or do you want me to change that in 10 too? >> > Well, there are spare fields (if_ispare[4]) in struct ifnet that I > believe can be used for new u_ints when MFC'ng a patch that adds > fields to struct ifnet in head. (If I have this wrong, someone please > correct me.) > > I'll admit I don't really see an advantage to defining a structure vs > just defining a couple of additional u_ints, but so long as the structure > doesn't cause alignment issues for any arch, I don't see a problem with > a structure. > > I tend to agree with Adrian that this shouldn't be rushed. (I, personally, > think that if_hw_tsomax was poorly chosen, but that is already in use, so > I think we need to add to that and not replace it.) > > I also hope that your testing has included quite a bit of activity on > an NFS mount using TSO and the default 64K rsize, wsize, since that is > going to generate a bunch of 35 mbuf transmit fragment lists and there > is an edge case where the total data length excluding ethernet header > is just under 64K (by less than the ethernet header length) where the > list must be split by tcp_output() to avoid disaster. Hi, The ethernet and VLAN headers are still subtracted. --HPS
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