From mboxrd@z Thu Jan 1 00:00:00 1970 From: swise@opengridcomputing.com (Steve Wise) Date: Wed, 9 May 2018 13:46:19 -0500 Subject: [PATCH RFC 0/2] 8K Inline Support In-Reply-To: References: Message-ID: <190dc0f4-35c0-7424-8b38-6ff27ef255d7@opengridcomputing.com> On 5/9/2018 10:38 AM, Steve Wise wrote: > For small nvmf write IO over the rdma transport, it is advantagous to > make use of inline mode to avoid the latency of the target issuing an > rdma read to fetch the data. Currently inline is used for <= 4K writes. > 8K, though, requires the rdma read. For iWARP transports additional > latency is incurred because the target mr of the read must be registered > with remote write access. By allowing 2 pages worth of inline payload, > I see a reduction in 8K nvmf write latency of anywhere from 2-7 usecs > depending on the RDMA transport.. > > Is this a worthwhile change? I think it is. Please comment! > > Thanks, > > Steve By the way, this patch series is untested on the current top-of-tree; I ported it from an older 4.9 kernel where I was doing the performance testing.? As the series is RFC, I'm just looking for whether folks think this is a "good idea" or not.?? So I'll post something that is ready to merge if I get positive feedback on moving forward. Steve.