On 9/4/25 10:42 AM, Mike Snitzer wrote: > On Tue, Sep 02, 2025 at 05:27:11PM -0400, Mike Snitzer wrote: >> On Tue, Sep 02, 2025 at 05:16:10PM -0400, Chuck Lever wrote: >>> >>> I am testing with a physically separate client and server, so I believe >>> that LOCALIO is not in play. I do see WRITEs. And other workloads (in >>> particular "fsx -Z <fname>") show READ traffic and I'm getting the >>> new trace point to fire quite a bit, and it is showing misaligned >>> READ requests. So it has something to do with dt. >> >> OK, yeah I figured you weren't doing loopback mount, only thing that >> came to mind for you not seeing READ like expected. I haven't had any >> problems with dt not driving READs to NFSD... >> >> You'll certainly need to see READs in order for NFSD's new misaligned >> DIO READ handling to get tested. > > I was doing some additional testing of the v9 changes last night and > realized why you weren't seeing any READs come through to NFSD: > "flags=direct" must be added to the dt commandline. Otherwise it'll > use buffered IO at the client and the READ will be serviced by the > client's page cache. > > But like I said in another reply: when I just use v3 and RDMA (without > the intermediary of flexfiles at the client) I'm not able to see the > data mismatch with dt... > > So while its unlikely: does adding "flags=direct" cause dt to fail > when NFSD handles the misaligned DIO READ? That make sense, I will give that a shot and let you know. -- Chuck Lever
