Re: [PATCH rdma-next] RDMA/rdmavt: Decouple QP and SGE lists allocations

From: Leon Romanovsky <leon@kernel.org>
To: Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>
Cc: "Marciniszyn, Mike" <mike.marciniszyn@cornelisnetworks.com>,
	Doug Ledford <dledford@redhat.com>,
	Jason Gunthorpe <jgg@nvidia.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH rdma-next] RDMA/rdmavt: Decouple QP and SGE lists allocations
Date: Sun, 16 May 2021 13:56:05 +0300	[thread overview]
Message-ID: <YKD6ReulqPQNGScG@unreal> (raw)
In-Reply-To: <7e7c411b-572b-6080-e991-deb324e3d0e2@cornelisnetworks.com>

On Thu, May 13, 2021 at 03:03:43PM -0400, Dennis Dalessandro wrote:
> On 5/12/21 8:50 AM, Leon Romanovsky wrote:
> > On Wed, May 12, 2021 at 12:25:15PM +0000, Marciniszyn, Mike wrote:
> > > > > Thanks Leon, we'll get this put through our testing.
> > > > 
> > > > Thanks a lot.
> > > > 
> > > > > 
> > > 
> > > The patch as is passed all our functional testing.
> > 
> > Thanks Mike,
> > 
> > Can I ask you to perform a performance comparison between this patch and
> > the following?
> 
> We have years of performance data with the code the way it is. Please
> maintain the original functionality of the code when moving things into the
> core unless there is a compelling reason to change. That is not the case
> here.

Sorry for not being responsive.

In addition to already said in parallel thread, this change keeps the
functionality except static node. I'm curious to finally see the difference
between these two allocations and it is very unlilkely we will see any.

For example, this QP can be associated with application that runs on
different node than rdi->dparms.node. Will we see performance degradation?

Thanks