On Mon, Apr 05, 2021 at 03:41:15PM +0200, Christoph Hellwig wrote: > On Mon, Apr 05, 2021 at 08:23:54AM +0300, Leon Romanovsky wrote: > > From: Leon Romanovsky <leonro@xxxxxxxxxx> > > > > >From Avihai, > > > > Relaxed Ordering is a PCIe mechanism that relaxes the strict ordering > > imposed on PCI transactions, and thus, can improve performance. > > > > Until now, relaxed ordering could be set only by user space applications > > for user MRs. The following patch series enables relaxed ordering for the > > kernel ULPs as well. Relaxed ordering is an optional capability, and as > > such, it is ignored by vendors that don't support it. > > > > The following test results show the performance improvement achieved > > with relaxed ordering. The test was performed on a NVIDIA A100 in order > > to check performance of storage infrastructure over xprtrdma: > > Isn't the Nvidia A100 a GPU not actually supported by Linux at all? > What does that have to do with storage protocols? I think it is a typo (or at least mit makes no sense to be talking about NFS with a GPU chip) Probably it should be a DGX A100 which is a dual socket AMD server with alot of PCIe, and xptrtrdma is a NFS-RDMA workload. AMD dual socket systems are well known to benefit from relaxed ordering, people have been doing this in userspace for a while now with the opt in. What surprises me is the performance difference, I hadn't heard it is 4x! Jason
