Date: Sun, 23 Sep 2007 13:31:50 +0400 From: "Artem Kuchin" <matrix@itlegion.ru> To: "Jack Vogel" <jfvogel@gmail.com> Cc: freebsd-current@freebsd.org Subject: Re: TSP on em makes send of streams very slow Message-ID: <003201c7fdc4$948749a0$0c00a8c0@Artem> References: <01c801c7fc7a$696ab900$0c00a8c0@Artem><2a41acea0709211359w37ba779dsec94de504a9f4a9c@mail.gmail.com><019101c7fd3d$cd15f870$0c00a8c0@Artem> <2a41acea0709221647o3cdcb72pf6194c54782c61fb@mail.gmail.com>
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Jack Vogel wrote: > On 9/22/07, Artem Kuchin <matrix@itlegion.ru> wrote: >>> TSO is for some environments, it isn't gonna be useful at 100Mb >>> (which you are), it can be useful at 1Gb but not always, when you >>> get to 10G its >>> a HUGE benefit. >>> >>> Just cuz you can shoot yourself in the foot doesn't mean the gun >>> has a problem :) >> >> But wait, i did not shoot myself. I have been shot by the driver w/o >> any preliminary warning. TSO4 was enabled by DEFAULT (i did not >> enable it), >> so anybody can be in my place if used the same driver on the similar >> hardware (which is plenty). >> >> So, i think this is a problem which really need to be addressed. > > It is on by default because it the majority of cases its a benefit, > you found it to be a problem and turned it off, your problem is > solved. > > I admit, at one point I considered disabling it automatically for > anything under Gig speed, but a large community has used this driver > with this feature for over a year, no one has lobbied to have to > disabled, so I have not. > > If there are others who think this would be a good idea, speak up, and > I will do so. > Disable it by default is not actually the point. There are three points: 1) I have wasted half a work day to figure it all out 2) I expect at least network part of *FREEBSD* OS to work right out of the box 3) Even having it enabled must not cause drop to 800 bytes/second on send. This is clearly a bug. I don;t know if it is hardware of software bug but it must be addressed in the driver anyway. Or, as an option there must be a big waving banner somewhere where noone can miss it saying: "If you have crazy drop in network send perfomance disable TSO on your NIC via ifconfig". -- Regards, Artem
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