Re: r8169 & TX offload

[Francois Romieu]

(please remove l-k from the Cc:, this ought to be sent to netdev)

Vladislav Bolkhovitin <vst@xxxxxxxx> :
>
> I've recently bought Realtek RTL8169S-32 chip based Gigabit Ethernet card:
> 
> # lspci -vv
[...]
> I've noticed that all TX offload features (tx-checksumming, 
> scatter-gather and TSO) are disabled by default and should be manually 
> enabled by ethtool. I wonder, is there any particular reason for that? 

As far as I can tell, it is mostly a lack of pressure from the users and
my desire to avoid a change of behavior.

> Why they are not enabled by default as it was done for e1000 or tg3? Are 
> there any hidden drawbacks in enabling them?

None that I know of. I had not noticed a huge difference and people did
not comment a lot either...

> Those offload options are definitely work. They give in my setup (32-bit 
> 66MHz PCI, Xeon 1.7GHz CPU, open-iscsi) CPU offload from 75% to 45% and 
> data write throughput improvement from 55MB/s to 59MB/s.

...but your datapoint is welcome.

-- 
Ueimor
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