Re: TSP on em makes send of streams very slow

On 9/21/07, Artem Kuchin <matrix_at_itlegion.ru> wrote:
> Hello!
>
> Here is what i have experienced today.
>
> I just installed  7.0-CURRENT (cvsed and build on 2007/09/20)
> on a PRODUCTION web server
> (because, IHMO, this current is stable enough and i like
> too much :)
>
> This is intel MB with two built-in em intefaces.
>
> I sshed to the server.
> While i was in plain shell everything was fine, but when i
> stared midnight commander i saw how it very slowly draws
> scren part by part. It took about 3 monutes to almost
> completely draw a screen when i got disconnected. I tied again
> - the same. Then i connected via ftp and uploaded 10MB file
> at 900KB/sec. When i tried to download it back  i got about
> 500 *BYTES*/sec and the got disconnected in a couple of minutes.
>
> Ping was just find, even flood ping from the server on the save
> switch with 15000 packets was fine (just one dot on the left).
>
> I went also crazy already when i desided to compare interface params
> with another server with em NICs.
>
> The dfference is that this is has the following options (by DEFAULT,
> i did not turn it on):
>
> VLAN_HWCSUM,TSO4
>
> I've read about TSO on 'man ifconfig' and just for kicks decided
> to turn it off. VOILA!!! In a seconds send speed was up to 10 MBYTES/sec!
>
> I have googled about 'em tso slow ' etc.. and found a couple of seemingly
> the same problem dated back 2006. Is it supposed to be solved by now?
> What IS the problem with TSO?

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 :)

Jack