> On Jan 3, 2019, at 4:28 PM, Trond Myklebust <trondmy@xxxxxxxxxxxxxxx> wrote: > > On Thu, 2019-01-03 at 16:07 -0500, Chuck Lever wrote: >>> 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) >> > > So about a 5% reduction in performance? On this workload, yes. Could send the record marker in xs_send_kvec with the head[0] iovec. I'm going to try that next. -- Chuck Lever
