From: Trond Myklebust <trondmy@hammerspace.com>
To: "chuck.lever@oracle.com" <chuck.lever@oracle.com>
Cc: "linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: [PATCH] SUNRPC: Remove rpc_xprt::tsh_size
Date: Fri, 4 Jan 2019 04:00:11 +0000 [thread overview]
Message-ID: <1d6779ff05f2d31c4eccd048acbb28563bc9b79b.camel@hammerspace.com> (raw)
In-Reply-To: <CE340D31-4F14-4C6F-B7C8-958754394C08@oracle.com>
On Thu, 2019-01-03 at 17:49 -0500, Chuck Lever wrote:
> > On Jan 3, 2019, at 4:35 PM, Chuck Lever <chuck.lever@oracle.com>
> > wrote:
> >
> > > On Jan 3, 2019, at 4:28 PM, Trond Myklebust <
> > > trondmy@hammerspace.com> 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@oracle.com>
> > > > > wrote:
> > > > >
> > > > > > On Jan 3, 2019, at 1:47 PM, Trond Myklebust <
> > > > > > trondmy@hammerspace.com> 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.
>
> That helps:
>
> Linux 4.20.0-rc7-00049-g664f679 #651 SMP Thu Jan 3 17:35:26 EST 2019
>
> read: IOPS=28.7k, BW=224MiB/s (235MB/s)(11.2GiB/51185msec)
> write: IOPS=12.3k, BW=96.1MiB/s (101MB/s)(4919MiB/51185msec)
>
Interesting... Perhaps we might be able to eke out a few more percent
performance on file writes by also converting xs_send_pagedata() to use
a single sock_sendmsg() w/ iov_iter rather than looping through several
calls to sendpage()?
--
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com
next prev parent reply other threads:[~2019-01-04 4:00 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-03 18:29 [PATCH] SUNRPC: Remove rpc_xprt::tsh_size Chuck Lever
2019-01-03 18:47 ` Trond Myklebust
2019-01-03 20:53 ` Chuck Lever
2019-01-03 21:07 ` Chuck Lever
2019-01-03 21:28 ` Trond Myklebust
2019-01-03 21:35 ` Chuck Lever
2019-01-03 22:49 ` Chuck Lever
2019-01-04 4:00 ` Trond Myklebust [this message]
2019-01-04 21:35 ` Chuck Lever
2019-01-04 22:44 ` Trond Myklebust
2019-01-10 17:13 ` Chuck Lever
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