> On Jan 3, 2019, at 3:53 PM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote: > >> On Jan 3, 2019, at 1:47 PM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: >> >> On Thu, 2019-01-03 at 13:29 -0500, Chuck Lever wrote: >>> >>> + reclen = req->rq_snd_buf.len; >>> + marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen); >>> + return kernel_sendmsg(transport->sock, &msg, &iov, 1, >>> iov.iov_len); >> >> >> So what does this do for performance? I'd expect that adding another >> dive into the socket layer will come with penalties. > > NFSv3 on TCP, sec=sys, 56Gbs IBoIP, v4.20 + my v4.21 patches > fio, 8KB random, 70% read, 30% write, 16 threads, iodepth=16 > > Without this patch: > > read: IOPS=28.7k, BW=224MiB/s (235MB/s)(11.2GiB/51092msec) > write: IOPS=12.3k, BW=96.3MiB/s (101MB/s)(4918MiB/51092msec) > > With this patch: > > read: IOPS=28.6k, BW=224MiB/s (235MB/s)(11.2GiB/51276msec) > write: IOPS=12.3k, BW=95.8MiB/s (100MB/s)(4914MiB/51276msec) > > Seems like that's in the noise. Sigh. That's because it was the same kernel. Again, with feeling: 4.20.0-rc7-00048-g9274254: read: IOPS=28.6k, BW=224MiB/s (235MB/s)(11.2GiB/51276msec) write: IOPS=12.3k, BW=95.8MiB/s (100MB/s)(4914MiB/51276msec) 4.20.0-rc7-00049-ga4dea15: read: IOPS=27.2k, BW=212MiB/s (223MB/s)(11.2GiB/53979msec) write: IOPS=11.7k, BW=91.1MiB/s (95.5MB/s)(4917MiB/53979msec) -- Chuck Lever
