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From: Alkis Georgopoulos <alkisg@gmail.com>
To: Trond Myklebust <trondmy@hammerspace.com>,
	"linux-nfs@vger.kernel.org" <linux-nfs@vger.kernel.org>
Subject: Re: rsize,wsize=1M causes severe lags in 10/100 Mbps
Date: Thu, 19 Sep 2019 22:57:09 +0300
Message-ID: <915fa536-c992-3b77-505e-829c4d049b02@gmail.com> (raw)
In-Reply-To: <e51876b8c2540521c8141ba11b11556d22bde20b.camel@hammerspace.com>

On 9/19/19 10:51 PM, Trond Myklebust wrote:
> I don't understand why klibc would default to supplying a timeo=7
> argument at all. It would be MUCH better if it just let the kernel set
> the default, which in the case of TCP is timeo=600.
> 
> I agree with your argument that replaying requests every 0.7 seconds is
> just going to cause congestion. TCP provides for reliable delivery of
> RPC messages to the server, which is why the kernel default is a full
> minute.
> 
> So please ask the klibc developers to change libmount to let the kernel
> decide the default mount options. Their current setting is just plain
> wrong.


This was what I asked in my first message to their mailing list,
https://lists.zytor.com/archives/klibc/2019-September/004234.html

Then I realized that timeo=600 just hides the real problem,
which is rsize=1M.

NFS defaults: timeo=600,rsize=1M => lag
nfsmount defaults: timeo=7,rsize=1MK => lag AND dmesg errors

My proposal: timeo=whatever,rsize=32K => all fine

If more benchmarks are needed from me to document the
"NFS defaults: timeo=600,rsize=1M => lag"
I can surely provide them.

Thanks,
Alkis

  reply index

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-19  7:29 rsize,wsize=1M causes severe lags in 10/100 Mbps, what sets those defaults? Alkis Georgopoulos
2019-09-19 15:08 ` Trond Myklebust
2019-09-19 15:58   ` rsize,wsize=1M causes severe lags in 10/100 Mbps Alkis Georgopoulos
2019-09-19 16:11     ` Trond Myklebust
2019-09-19 19:21       ` Alkis Georgopoulos
2019-09-19 19:51         ` Trond Myklebust
2019-09-19 19:57           ` Alkis Georgopoulos [this message]
2019-09-19 20:05             ` Trond Myklebust
2019-09-19 20:20               ` Alkis Georgopoulos
2019-09-19 20:40                 ` Trond Myklebust
2019-09-19 21:19                   ` Daniel Forrest
2019-09-19 21:42                     ` Trond Myklebust
2019-09-19 22:16                       ` Daniel Forrest
2019-09-20  9:25                         ` Alkis Georgopoulos
2019-09-20  9:48                           ` Alkis Georgopoulos
2019-09-20 10:04                             ` Alkis Georgopoulos
2019-09-21  7:52                               ` Alkis Georgopoulos
2019-09-21  7:59                                 ` Alkis Georgopoulos
2019-09-21 11:02                                   ` Alkis Georgopoulos

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