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From: Frans Pop <elendil-EIBgga6/0yRmR6Xm/wNWPw@public.gmane.org>
To: Trond Myklebust
	<trond.myklebust-41N18TsMXrtuMpJDpNschA@public.gmane.org>
Cc: linux-nfs-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Linux Kernel Mailing List
	<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
	netdev-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [2.6.30.1] Significant latency playing video file from NFS4 share
Date: Tue, 21 Jul 2009 19:31:48 +0200	[thread overview]
Message-ID: <200907211931.50015.elendil@planet.nl> (raw)
In-Reply-To: <200907180131.12586.elendil-EIBgga6/0yRmR6Xm/wNWPw@public.gmane.org>

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Any suggestions based on the data below?

Is the problem maybe that the amount of data transferred each time is so
big that the network speed becomes a bottleneck and causes the latency?
I can reproduce the issue with both a 10MBit wired link and with a 54MBit
wireless link.

Is this a kernel bug or a configuration issue?

Thanks,
FJP

On Saturday 18 July 2009, Frans Pop wrote:
> Thanks for the quick response!
>
> On Saturday 18 July 2009, Trond Myklebust wrote:
> > Have you tried running nfs-iostat from the nfs-utils package to try
> > and figure out what the latency is on each READ request from the
> > client?
> >
> > You need to run something like
> >
> >     nfs-iostat --page 20 10 /src/<mountpoint>
> >
> > while running the vlc app.

$ ../nfs-iostat.py --page 20 10 /srv/fjp/david

Note:
The mount point selection could be improved. I first had a trailing slash
after the mount point and that resulted in all mounts being included in the
output. Removing the slash helped.

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.65            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.406         101.661         250.613        0 (0.0%)         1211.745        1222.640
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

13 nfs_readpage() calls read 13 pages
1417 nfs_readpages() calls read 971428 pages (685.6 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
18760 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.25            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.100           0.426           4.262        0 (0.0%)           6.000           6.000
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
2 nfs_readpages() calls read 2 pages (1.0 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.80            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.750         192.196         256.262        0 (0.0%)         1998.933        1999.200
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
1 nfs_readpages() calls read 960 pages (960.0 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.00            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
0 nfs_readpages() calls read 0 pages

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.85            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.750         192.196         256.262        0 (0.0%)         1927.467        1927.467
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
1 nfs_readpages() calls read 960 pages (960.0 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.00            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
0 nfs_readpages() calls read 0 pages

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.85            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.750         192.196         256.262        0 (0.0%)         1930.933        1931.467
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
1 nfs_readpages() calls read 960 pages (960.0 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
5 nfs_writepages() calls wrote 0 pages (0.0 pages per call)

elrond:/david mounted on /srv/fjp/david:

   op/s         rpc bklog
   0.15            0.00
read:             ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.100           0.426           4.262        0 (0.0%)           6.000           6.000
write:            ops/s            kB/s           kB/op         retrans         avg RTT (ms)    avg exe (ms)
                  0.000           0.000           0.000        0 (0.0%)           0.000           0.000

0 nfs_readpage() calls read 0 pages
2 nfs_readpages() calls read 2 pages (1.0 pages per call)

0 nfs_updatepage() calls
0 nfs_writepage() calls wrote 0 pages
6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
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  parent reply	other threads:[~2009-07-21 17:31 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-17 20:50 [2.6.30.1] Significant latency playing video file from NFS4 share Frans Pop
2009-07-17 22:51 ` Trond Myklebust
     [not found]   ` <1247871086.4945.38.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-07-17 23:31     ` Frans Pop
     [not found]       ` <200907180131.12586.elendil-EIBgga6/0yRmR6Xm/wNWPw@public.gmane.org>
2009-07-21 17:31         ` Frans Pop [this message]
     [not found]           ` <200907211931.50015.elendil-EIBgga6/0yRmR6Xm/wNWPw@public.gmane.org>
2009-07-21 17:58             ` Trond Myklebust
     [not found]               ` <1248199105.21343.16.camel-rJ7iovZKK19ZJLDQqaL3InhyD016LWXt@public.gmane.org>
2009-07-21 21:54                 ` Frans Pop

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