FileRead() with F_NOCACHE doesn't jive with NFS on MacOS
The default size for NFS reads on 10.8.3 is 32KB, but VLC generally reads less than 2KB. As an NFSv3 client MacOS takes F_NOCACHE very literally, so for each sequential 2KB read, it reads the same 32KB 16 times (I have the network traces to provei it). The result is that a file with a relatively low bit rate (<16Mbps) becomes unplayable over WiFi.
A partial workaround is to specify a smaller rsize with nfs_mount, but this becomes self-defeating due to increased NFS chatter.
A much better solution would be for VLC to do larger reads (e.g. 32KB or more). A while ago I posted this ...
http://forum.videolan.org/viewtopic.php?f=12&t=96489
... which includes some DTrace output, and some attempts to workaround using the Mmap module, but it got no bites. The most interesting issue appears to be that FileRead() size seems pretty random and impossible to predict (even from run to run of the same stream). Fix that, and lots of things could run more sweetly.