RE: [[PATCH v1] 12/37] [CIFS] SMBD: Handle send completion from CQ

[Long Li]

> -----Original Message-----
> From: Christoph Hellwig [mailto:hch@xxxxxxxxxxxxx]
> Sent: Sunday, August 13, 2017 3:20 AM
> To: Long Li <longli@xxxxxxxxxxxxx>
> Cc: Steve French <sfrench@xxxxxxxxx>; linux-cifs@xxxxxxxxxxxxxxx; samba-
> technical@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Long Li
> <longli@xxxxxxxxxxxxx>
> Subject: Re: [[PATCH v1] 12/37] [CIFS] SMBD: Handle send completion from
> CQ
> 
> You seem to be doing memory allocations and frees for every packet on the
> write.  At least for other RDMA protocols that would have been a major
> performance issue.

The size of SGE array passed to IB is unknown, so I don't know how much to pre-allocate in advance. But it seems this size is not big when passed down from CIFS. I will look at pre-allocating buffer if this is an issue.

> 
> Do you have any performance numbers and/or profiles of the code?

I will look into profiling.