On Tue, Feb 16, 2021 at 5:27 PM Timo Rothenpieler <timo@xxxxxxxxxxxxxxxx> wrote: > > On 16.02.2021 21:37, Timo Rothenpieler wrote: > > I can't get a network (I assume just TCP/20049 is fine, and not also > > some RDMA trace?) right now, but I will once a user has finished their > > work on the machine. > > There wasn't any TCP traffic to dump on the NFSoRDMA Port, probably > because everything is handled via RDMA/IB. Yeah, I'm not sure if tcpdump can snoop on the IB traffic. I know that upstream tcpdump can snoop on RDMA mellanox card (but I only know about the Roce mode). > But I recorded a trace log of rpcrdma and sunrpc observing the situation. > > To me it looks like the COPY task (task:15886@7) completes successfully? > The compressed trace.dat is attached. I'm having a hard time reproducing the problem. But I only tried "xfs", "btrfs", "ext4" (first two send a CLONE since the file system supports it), the last one exercises a copy. In all my tries your xfs_io commands succeed. The differences between our environments are (1) ZFS vs (xfs, etc) and (2) IB vs RoCE. Question is: does any copy_file_range work over RDMA/IB. One thing to try a synchronous copy: create a small file 10bytes and do a copy. Is this the case where we have copy and the callback racing, so instead do a really large copy: create a >=1GB file and do a copy. that will be an async copy but will not have a racy condition. Can you try those 2 examples for me? Not sure how useful tracepoints here are. The results of the COPY isn't interesting as this is an async copy. The server should have sent a CB_COMPOUND with the copy's results. The process stack tells me that COPY is waiting for the results (waiting for the callback). So the question is there a problem of sending a callback over RDMA/IB? Or did the client receive it and missed it somehow? We really do need some better tracepoints in the copy (but we don't have them currently). Would you be willing to install the upstream libpcap/tcpdump to see if it can capture RDMA/IB traffic or perhaps Chunk knows that it doesn't work for sure? Thank you.
