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/> >> > 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++%ݶw{.n+{G{ayʇڙ,jfhz_(階ݢj"mG?&~iOzv^m ?I