RE: [ofa-general] Re: [PATCH RFC] RDMA/CMA: Allocate PS_TCPportsfrom the host TCP port space.

[Felix Marti]

> -----Original Message-----
> From: ak@xxxxxxx [mailto:ak@xxxxxxx] On Behalf Of Andi Kleen
> Sent: Sunday, August 19, 2007 4:28 PM
> To: Felix Marti
> Cc: David Miller; jeff@xxxxxxxxxx; netdev@xxxxxxxxxxxxxxx;
> rdreier@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> general@xxxxxxxxxxxxxxxxxxxxx
> Subject: Re: [ofa-general] Re: [PATCH RFC] RDMA/CMA: Allocate
> PS_TCPportsfrom the host TCP port space.
> 
> "Felix Marti" <felix@xxxxxxxxxxx> writes:
> 
> > what benefits does the TSO infrastructure give the
> > non-TSO capable devices?
> 
> It improves performance on software queueing devices between guests
> and hypervisors. This is a more and more important application these
> days.  Even when the system running the Hypervisor has a non TSO
> capable device in the end it'll still save CPU cycles this way. Right
> now
> virtualized IO tends to much more CPU intensive than direct IO so any
> help it can get is beneficial.
> 
> It also makes loopback faster, although given that's probably not that
> useful.
> 
> And a lot of the "TSO infrastructure" was needed for zero copy TX
> anyways,
> which benefits most reasonable modern NICs (anything with hardware
> checksumming)
Hi Andi, yes, you're right. I should have chosen my example more
carefully.

> 
> -Andi
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