For interested parties, Work on said branch is done so far and I think it is generally ready for being merged into /trunk. But it is certainly a good idea to give it some detailed review, in particular with regard to side- effects on e.g. FSFS recovery code.
What it does in a nutshell: * to FSFS svn_fs_t, attaches a cache for open file handles to reduce the number of open, lseek, read and close operations * svnserve CL and apache config option to set the per-process maximum of cached handles (default: 16) * use cached file handles for r/o access to revision files in FSFS * notify the cache after revision files have been written ("flush" cache entries for these files) With the repository on a linux RAM disk, it speeds up a "cold" export of TSVN /trunk by approx. 10%. Slower disks may show larger gains. If there are no major objections, I would like to merge the code into /trunk around mid-January. -- Stefan^2.