On May 24, 2010, at 2:05 PM, Les Mikesell wrote: > On 5/24/2010 3:51 PM, David Brodbeck wrote: >> >> On May 21, 2010, at 8:23 AM, Hyrum K. Wright wrote: >>> Actually, Subversion is a bit more intelligent about it, attempting to use >>> modification times and sizes, before doing a byte-by-byte comparison. >> >> Even that can be slow if there are lots of files involved. Note that some >> filesystems have particularly bad performance if there are lots of files in >> a single directory, as well. This is especially true of NFS. In one >> extreme example, I've seen a simple "ls" take tens of minutes to produce any >> output in an NFS-mounted directory with ~1,000,000 files. > > But to be fair, note that ls sorts its output, so it can't output anything > until it has read everything.
True, but other operations were slow, too. The way readdir() works means that a lot of file operations inevitably involve a linear search of the directory. -- David Brodbeck System Administrator, Linguistics University of Washington
