Any suggestions based on the data below?
Is the problem maybe that the amount of data transferred each time is sobig 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 54MBitwireless 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 slashafter the mount point and that resulted in all mounts being included in theoutput. Removing the slash helped.
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.65 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.406 101.661 250.613 0 (0.0%) 1211.745 1222.640write: 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 pages1417 nfs_readpages() calls read 971428 pages (685.6 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages18760 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.25 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.100 0.426 4.262 0 (0.0%) 6.000 6.000write: 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 pages2 nfs_readpages() calls read 2 pages (1.0 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.80 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.750 192.196 256.262 0 (0.0%) 1998.933 1999.200write: 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 pages1 nfs_readpages() calls read 960 pages (960.0 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.00 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.000 0.000 0.000 0 (0.0%) 0.000 0.000write: 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 pages0 nfs_readpages() calls read 0 pages
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.85 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.750 192.196 256.262 0 (0.0%) 1927.467 1927.467write: 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 pages1 nfs_readpages() calls read 960 pages (960.0 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.00 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.000 0.000 0.000 0 (0.0%) 0.000 0.000write: 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 pages0 nfs_readpages() calls read 0 pages
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.85 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.750 192.196 256.262 0 (0.0%) 1930.933 1931.467write: 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 pages1 nfs_readpages() calls read 960 pages (960.0 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages5 nfs_writepages() calls wrote 0 pages (0.0 pages per call)
elrond:/david mounted on /srv/fjp/david:
op/s rpc bklog 0.15 0.00read: ops/s kB/s kB/op retrans avg RTT (ms) avg exe (ms) 0.100 0.426 4.262 0 (0.0%) 6.000 6.000write: 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 pages2 nfs_readpages() calls read 2 pages (1.0 pages per call)
0 nfs_updatepage() calls0 nfs_writepage() calls wrote 0 pages6 nfs_writepages() calls wrote 0 pages (0.0 pages per call)��.n��������+%������w��{.n�����{��w��� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
