From: Tom Talpey <tom@talpey.com>
To: Bruce Fields <bfields@fieldses.org>,
Chuck Lever <chuck.lever@oracle.com>
Cc: Linux NFS Mailing List <linux-nfs@vger.kernel.org>
Subject: Re: unsharing tcp connections from different NFS mounts
Date: Tue, 6 Oct 2020 13:07:11 -0400 [thread overview]
Message-ID: <bb58e43a-f23d-d5f5-ac53-9230267f7faa@talpey.com> (raw)
In-Reply-To: <20201006152223.GD28306@fieldses.org>
On 10/6/2020 11:22 AM, Bruce Fields wrote:
> On Tue, Oct 06, 2020 at 11:20:41AM -0400, Chuck Lever wrote:
>>
>>
>>> On Oct 6, 2020, at 11:13 AM, bfields@fieldses.org wrote:
>>>
>>> NFSv4.1+ differs from earlier versions in that it always performs
>>> trunking discovery that results in mounts to the same server sharing a
>>> TCP connection.
>>>
>>> It turns out this results in performance regressions for some users;
>>> apparently the workload on one mount interferes with performance of
>>> another mount, and they were previously able to work around the problem
>>> by using different server IP addresses for the different mounts.
>>>
>>> Am I overlooking some hack that would reenable the previous behavior?
>>> Or would people be averse to an "-o noshareconn" option?
>>
>> I thought this was what the nconnect mount option was for.
>
> I've suggested that. It doesn't isolate the two mounts from each other
> in the same way, but I can imagine it might make it less likely that a
> user on one mount will block a user on another? I don't know, it might
> depend on the details of their workload and a certain amount of luck.
Wouldn't it be better to fully understand the reason for the
performance difference, before changing the mount API? If it's
a guess, it'll come back to haunt the code for years.
For example, maybe it's lock contention in the xprt transport code,
or in the socket stack.
Just askin'.
Tom.
next prev parent reply other threads:[~2020-10-06 17:14 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-06 15:13 unsharing tcp connections from different NFS mounts J. Bruce Fields
2020-10-06 15:20 ` Chuck Lever
2020-10-06 15:22 ` Bruce Fields
2020-10-06 17:07 ` Tom Talpey [this message]
2020-10-06 19:30 ` Bruce Fields
[not found] ` <CAGrwUG5_KeRVR8chcA8=3FSeii2+4c8FbuE=CSGAtYVYqV4kLg@mail.gmail.com>
2020-10-07 14:08 ` Tom Talpey
2020-10-06 19:36 ` Benjamin Coddington
2020-10-06 21:46 ` Olga Kornievskaia
2020-10-07 0:18 ` J. Bruce Fields
2020-10-07 11:27 ` Benjamin Coddington
2020-10-07 12:55 ` Benjamin Coddington
2020-10-07 13:45 ` Chuck Lever
2020-10-07 14:05 ` Bruce Fields
2020-10-07 14:15 ` Chuck Lever
2020-10-07 16:05 ` Bruce Fields
2020-10-07 16:44 ` Trond Myklebust
2020-10-07 17:15 ` Bruce Fields
2020-10-07 17:29 ` Trond Myklebust
2020-10-07 18:05 ` bfields
2020-10-07 19:11 ` Trond Myklebust
2020-10-07 20:29 ` bfields
2020-10-07 18:04 ` Benjamin Coddington
2020-10-07 18:19 ` Trond Myklebust
2020-10-07 16:50 ` Trond Myklebust
2021-01-19 22:22 ` bfields
2021-01-19 23:09 ` Trond Myklebust
2021-01-20 15:07 ` bfields
2021-05-03 20:09 ` bfields
2021-05-04 2:08 ` NeilBrown
2021-05-04 13:27 ` Tom Talpey
2021-05-04 14:27 ` Trond Myklebust
2021-05-04 16:51 ` bfields
2021-05-04 21:32 ` Daire Byrne
2021-05-04 21:48 ` Trond Myklebust
2021-05-05 12:53 ` Daire Byrne
2021-01-20 15:58 ` Chuck Lever
2020-10-07 13:56 ` Patrick Goetz
2020-10-07 16:28 ` Igor Ostrovsky
2020-10-07 16:30 ` Benjamin Coddington
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=bb58e43a-f23d-d5f5-ac53-9230267f7faa@talpey.com \
--to=tom@talpey.com \
--cc=bfields@fieldses.org \
--cc=chuck.lever@oracle.com \
--cc=linux-nfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).