[openib-general] RE: SDP and Socket Options

[Majumder, Rajib]

1) which sdp calls the "read" and "write" are mapped to?
2) sdp latency is quite high compared to other userspace socket implementation. The fastest socket has 2.26us latency over a SCI (IEEE 1596)link. Any plan for userspace? 
3) Any plan for a socket layer over uDAPL? 
4) Currently, IPoIB has huge cpu overhead for obvious reasons. Any plan for a module that will bypass kernel resident tcp/ip stack and at the same time support UDP over RC? UDP applications are benefitted from this. Currently, all IP multicast based middlewares use UDP. 

thanks.

rajib  

-----Original Message-----
From: Michael S. Tsirkin [mailto:mst at mellanox.co.il]
Sent: 30 August 2005 15:22
To: Majumder, Rajib
Cc: openib-general at openib.org
Subject: Re: SDP and Socket Options


Quoting Majumder, Rajib <rajib.majumder at csfb.com>:
> Subject: SDP and Socket Options
> 
> hello, 
> i am trying to figure out, as of now, what socket stuff are NOT supported by SDP. this will help me identify the gaps between the 2. 

When you say SDP, I assume you are talking about creating a socket
with the AF_INET_SDP family.

> can you point me toward some docs that may describe these gaps? 

You'll have to look at the source. Get it here:
https://openib.org/svn/gen2/trunk/src/linux-kernel/infiniband/ulp/sdp/

Its actually not that big: around 16000 lines (including comments).
sdp_inet.c is a good starting point - thats where we register
the new protocol family. That file is 1461 lines.

> 1) what socket system calls are not supported? 

I think all of them work at this point.

> 2) what socket options are not supported? 

IPv6 addressing is probably the biggest omission.
This actually shouldnt be hard to fix, given enough interest.

I didnt look into this in depth yet, but I think SO_{RCV,SND}BUF
just set sk_rcvbuf/sk_sendbuf in the socket structure, which
then isnt used in any way.

> 3) other stuff - keepalives etc 
> thanks. 
> rajib 

Keepalives is the only missing point that I know about.

-- 
MST


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