Date: Wed, 26 Feb 2014 13:13:36 -0800 From: Scott Long <scott4long@yahoo.com> To: Jack Vogel <jfvogel@gmail.com> Cc: FreeBSD Net <freebsd-net@freebsd.org>, Sami Halabi <sodynet1@gmail.com> Subject: Re: TSO Message-ID: <D42D04B4-C79C-4679-A70A-9AFF7081CADB@yahoo.com> In-Reply-To: <CAFOYbckc8=j1kAU097Y=2UjFS747O49vuWYBDLmxOqXUAOkBhw@mail.gmail.com> References: <CAEW%2BogYVto3rr6LHVsG4rOuyhXt3ZWbH2kWNk-1kAmwDKROEqg@mail.gmail.com> <20140226180736.GV92037@funkthat.com> <CAFOYbckc8=j1kAU097Y=2UjFS747O49vuWYBDLmxOqXUAOkBhw@mail.gmail.com>
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Are you proposing that the network stack track the physical memory segment details of the mbufs as they are formed and chained together? Scott On Feb 26, 2014, at 10:27 AM, Jack Vogel <jfvogel@gmail.com> wrote: > Drivers have to work with whatever the requirements/limitations of the > hardware, > if you have a 5 lb sack you shouldn't be surprised if some drops when you > shove > 6 lbs at it :) > > Why not have this limit in the interface so the stack can avoid exceeding > it? > > Jack > > > > > On Wed, Feb 26, 2014 at 10:07 AM, John-Mark Gurney <jmg@funkthat.com> wrote: > >> Sami Halabi wrote this message on Wed, Feb 26, 2014 at 19:37 +0200: >>> I'm reading (almost) all mailing emails in mailig list... >>> >>> Almost every / many problem in network performancr / packets loss ended >> up >>> suggesting disabling TSO. >>> >>> I wonder why.. Is it a bug in the implementation? Or bybdesign? >>> What are the usecases that TSO is needed? Myabe it should be disabled bt >>> default? >> >> It looks like most of the problems are in drivers that don't handle >> packets with a large number of segments properly... The problem is >> that some drivers limit to how segments a packet can be broken into, and >> then if they receive such a packet, instead of doing their darnest to >> deliver it, they drop it... >> >> There are some patches that help address the issue... >> >> Drivers should complain more loudly when a packet gets dropped by the >> driver, since it is likely that the OS may retry the same packet, >> just to have it fail, though sometimes it'll try a different set, and >> it might go through, so all the user may notice is a slight lag if >> they notice anything at all... >> >> -- >> John-Mark Gurney Voice: +1 415 225 5579 >> >> "All that I will do, has been done, All that I have, has not." >> _______________________________________________ >> 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" >> > _______________________________________________ > 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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