On Fri, 2009-07-17 at 22:50 +0200, Frans Pop wrote: > While playing a video (avi) file from an nfs4 share using vlc I'm getting > significant latencies on the client resulting in video skips every 10-30 > seconds. latencytop gives me for example: > > Cause Maximum Percentage > rpc_wait_bit_killable __rpc_execute > rpc_execute rp[...] 2638.5 msec 46.1 % > Scheduler: waiting for cpu 25.1 msec 19.9 % > Waiting for event (select) 5.0 msec 23.0 % > Waiting for event (poll) 4.8 msec 0.3 % > Userspace lock contention 4.6 msec 9.9 % > Waiting for data on unix socket 1.7 msec 0.8 % > > Process vlc (6681) Total: 2790.2 msec > rpc_wait_bit_killable __rpc_execute > rpc_execute rp[...] 2638.5 msec 94.6 % [1] > Scheduler: waiting for cpu 9.3 msec 1.5 % > Waiting for event (poll) 4.8 msec 0.6 % > Userspace lock contention 4.3 msec 3.3 % > Waiting for event (select) 0.6 msec 0.1 % > > [1] nfs4_proc_getattr nfs4_proc_getattr __nfs_revalidate_inode nfs_getattr > vfs_geta[...] > > There is no other NFS access going on at the time; just reading the single > file. No significant other processes running on either the client or the > server. latencytop on the server does not show any significant latencies. > > Both server and client are dual core x86_64 running 2.6.30.1 with > identical configs (attached); Debian stable. > > From /etc/exports on the server: > /srv/exports 10.19.66.0/24(rw,fsid=0,subtree_check,sync) > /srv/exports/myshare 10.19.66.0/24(rw,subtree_check,sync,mp,nohide) > > mount on the client: > elrond:/myshare on /srv/<mountpoint> type nfs4 (rw,addr=10.19.66.2) > > Cheers, > FJP 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? http://git.linux-nfs.org/?p=steved/nfs-utils.git;a=blob_plain;f=tools/nfs-iostat/nfs-iostat.py;hb=HEAD You need to run something like nfs-iostat --page 20 10 /src/<mountpoint> while running the vlc app. Trond -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
