[ovs-dev] [PATCH v5] userspace: Add TCP Segmentation Offload support

Ilya Maximets i.maximets at ovn.org
Fri Jan 17 23:08:06 UTC 2020


On 18.01.2020 00:03, Stokes, Ian wrote:
> Thanks all for review/testing, pushed to master.

OK, thanks Ian.

@Ben, even though this patch already merged, I'd ask you to take a look
at the code in case you'll spot some issues especially in non-DPDK related
parts.

Thanks.

Best regards, Ilya Maximets.


> 
> Regards
> Ian
> 
> -----Original Message-----
> From: dev <ovs-dev-bounces at openvswitch.org> On Behalf Of Stokes, Ian
> Sent: Friday, January 17, 2020 10:56 PM
> To: Flavio Leitner <fbl at sysclose.org>; dev at openvswitch.org
> Cc: Ilya Maximets <i.maximets at ovn.org>; txfh2007 <txfh2007 at aliyun.com>
> Subject: Re: [ovs-dev] [PATCH v5] userspace: Add TCP Segmentation Offload support
> 
> 
> 
> On 1/17/2020 9:54 PM, Stokes, Ian wrote:
>>
>>
>> On 1/17/2020 9:47 PM, Flavio Leitner wrote:
>>> Abbreviated as TSO, TCP Segmentation Offload is a feature which enables
>>> the network stack to delegate the TCP segmentation to the NIC reducing
>>> the per packet CPU overhead.
>>>
>>> A guest using vhostuser interface with TSO enabled can send TCP packets
>>> much bigger than the MTU, which saves CPU cycles normally used to break
>>> the packets down to MTU size and to calculate checksums.
>>>
>>> It also saves CPU cycles used to parse multiple packets/headers during
>>> the packet processing inside virtual switch.
>>>
>>> If the destination of the packet is another guest in the same host, then
>>> the same big packet can be sent through a vhostuser interface skipping
>>> the segmentation completely. However, if the destination is not local,
>>> the NIC hardware is instructed to do the TCP segmentation and checksum
>>> calculation.
>>>
>>> It is recommended to check if NIC hardware supports TSO before enabling
>>> the feature, which is off by default. For additional information please
>>> check the tso.rst document.
>>>
>>> Signed-off-by: Flavio Leitner <fbl at sysclose.org>
>>
>> Fantastic work here Flavio, quick turn arouround when needed.
>>
>> Acked
> 
> Are the any objectionions to merging this?
> 
> Theres been nothhing so far.
> 
> If no further objections I will merge this at the end of the hour?
> 
> BR
> Ian
>>
>> BR
>> Ian


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