[Pvfs2-developers] BMI send implemtations

[Scott Atchley]

Hi Rob,

I will ping them. We can easily expand the bits for the peer id to 20  
(or even 24).

Scott

On Aug 23, 2006, at 11:13 AM, Rob Ross wrote:

> Hi Scott,
>
> You might want to ping your colleagues at ORNL and see how many  
> distinct peers they expect on upcoming XT* systems. Could be more  
> than 64K, if they don't do I/O forwarding (which we at ANL all hope  
> for...).
>
> Rob
>
> Scott Atchley wrote:
>
>> MX provides 64 bits of match info for sends/recvs. I plan to  
>> partition the bits as follows:
>> bits    comment
>> 0-3    msg_type (conn_req, conn_ack, expected, unexpected, ...?)
>> 4-7    reserved for credits (if used)
>> 8-15     reserved
>> 15-31    peer id (16 bits => 65K peers)
>> 32-63    BMI tag
>> The conn_req and con_ack message types allow me to do a simple  
>> handshake to establish MX state (hostname, NIC index, endpoint  
>> index) and agree on a version number. I'm reserving bits for  
>> credits should flow control be necessary and another 8 bits for  
>> future use if needed. I am assuming that 65K peers will be enough  
>> for awhile. If you think that PVFS will be deployed on systems  
>> with more than 65K peers, I can pull from the reserved bits to  
>> increase this id. Lastly, I will pass the BMI tag, which is 32 bits.