> On May 4, 2017, at 9:45 AM, Chuck Lever <chuck.lever@xxxxxxxxxx> wrote:
>
> Hi Trond-
>
>
>> On Apr 28, 2017, at 1:25 PM, Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx> wrote:
>>
>> Allow the user to specify that the client should use multiple connections
>> to the server. For the moment, this functionality will be limited to
>> TCP and to NFSv4.x (x>0).
>
> Some initial reactions:
>
> - 5/5 could be squashed into this patch (2/5).
>
> - 4/5 adds support for using NFSv3 with a DS. Why can't you add NFSv3
> support for multiple connections in the non-pNFS case? If there is a
> good reason, it should be stated in 4/5's patch description or added
> as a comment somewhere in the source code.
>
> - Testing with a Linux server shows that the basic NFS/RDMA pieces
> work, but any OPEN operation gets NFS4ERR_GRACE, forever, when I use
> nconnect > 1. I'm looking into it.
>
> - Testing with a Solaris 12 server prototype that supports NFSv4.1
> works fine with nconnect=[23]. Not seeing much performance improvement
> there because the server is using QDR and a single SATA SSD.
>
> Thus I don't see a strong need to keep the TCP-only limitation. However,
> if you do keep it, the logic that implements the second sentence in the
> patch description above is added in 3/5. Should this sentence be in that
> patch description instead? Or, instead:
>
> s/For the moment/In a subsequent patch
Oops, I forgot to mention: mountstats data looks a little confused
when nconnect > 1. For example:
WRITE:
3075342 ops (131%)
avg bytes sent per op: 26829 avg bytes received per op: 113
backlog wait: 162.375128 RTT: 1.481101 total execute time: 163.861735 (milliseconds)
Haven't looked closely at that 131%, but it could be either the kernel
or the script itself is assuming one connection per mount.
>> Signed-off-by: Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>
>> ---
>> fs/nfs/internal.h | 1 +
>> fs/nfs/super.c | 10 ++++++++++
>> 2 files changed, 11 insertions(+)
>>
>> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
>> index 31b26cf1b476..31757a742e9b 100644
>> --- a/fs/nfs/internal.h
>> +++ b/fs/nfs/internal.h
>> @@ -117,6 +117,7 @@ struct nfs_parsed_mount_data {
>> char *export_path;
>> int port;
>> unsigned short protocol;
>> + unsigned short nconnect;
>> } nfs_server;
>>
>> struct security_mnt_opts lsm_opts;
>> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
>> index 54e0f9f2dd94..7eb48934dc79 100644
>> --- a/fs/nfs/super.c
>> +++ b/fs/nfs/super.c
>> @@ -76,6 +76,8 @@
>> #define NFS_DEFAULT_VERSION 2
>> #endif
>>
>> +#define NFS_MAX_CONNECTIONS 16
>> +
>> enum {
>> /* Mount options that take no arguments */
>> Opt_soft, Opt_hard,
>> @@ -107,6 +109,7 @@ enum {
>> Opt_nfsvers,
>> Opt_sec, Opt_proto, Opt_mountproto, Opt_mounthost,
>> Opt_addr, Opt_mountaddr, Opt_clientaddr,
>> + Opt_nconnect,
>> Opt_lookupcache,
>> Opt_fscache_uniq,
>> Opt_local_lock,
>> @@ -179,6 +182,8 @@ static const match_table_t nfs_mount_option_tokens = {
>> { Opt_mounthost, "mounthost=%s" },
>> { Opt_mountaddr, "mountaddr=%s" },
>>
>> + { Opt_nconnect, "nconnect=%s" },
>> +
>> { Opt_lookupcache, "lookupcache=%s" },
>> { Opt_fscache_uniq, "fsc=%s" },
>> { Opt_local_lock, "local_lock=%s" },
>> @@ -1544,6 +1549,11 @@ static int nfs_parse_mount_options(char *raw,
>> if (mnt->mount_server.addrlen == 0)
>> goto out_invalid_address;
>> break;
>> + case Opt_nconnect:
>> + if (nfs_get_option_ul_bound(args, &option, 1, NFS_MAX_CONNECTIONS))
>> + goto out_invalid_value;
>> + mnt->nfs_server.nconnect = option;
>> + break;
>> case Opt_lookupcache:
>> string = match_strdup(args);
>> if (string == NULL)
>> --
>> 2.9.3
>>
>> --
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>
> --
> Chuck Lever
>
>
>
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--
Chuck Lever
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