On Thu, Nov 05, 2009 at 01:43:59PM -0500, Andy Liebman wrote: > >The problem is the following: When creating a file we have > >to prove that the file does not exist in a different > >upper/lower case combination. Under Unix, the only way to > >prove this is to list the whole directory and do a case > >insensitive comparison on each existing file. > > > > > > Thank you SO much. Your suggestion totally solved the problem. It makes > sense when you think about it. > > Results: When capturing standard definition DPX files, CPU utilization > is now down at 7 percent (out of 400 percent) and holds steady forever > basically. I was able to capture 150,000 frames (83 minutes) before I > got bored and stopped my test. > > In addition, I'm now capturing HD-444 DPX files which run at about 260 > MB/sec and that's doing fine as well -- running at 37 percent total CPU > (out of 400 percent).
If you want to read them out at wire speed, you might want to look at the vfs_preopen module, part of Samba 3.4. In case you have latency problems, this module forks helper processes that open and read the next n files in sequence. It was written for exactly your application, out of a cluster file system with pretty high open latency we got almost 400MBytes/second with that module well tuned, regardless of the broken access pattern :-) Volker
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