Juergen, Could you try the current version of read_open_filename from:
http://libarchive.googlecode.com/svn/trunk/libarchive/archive_read_open_filename.c You should be able to just copy it into your FreeBSD source tree and recompile. Duane Hesser's comments clarified for me that disk and tape I/O do require fundamentally different strategies, so I refactored this code to clearly break out those strategies. This in turn allowed me to do some straightforward I/O optimization of the disk case, which sped up your example by about 100x. I have a 2G DVD here on which "tar tvf /dev/acd0" took 90s originally, takes 14s with your patch, and now takes only 0.6s. For comparison, after mounting the disk, "find /mnt" takes 1.6s (which drops to .1s after the cache is warmed). It would be interesting to also compare two ways of copying all of the files: "tar xvf /dev/acd0" on an unmounted disk and "cp -R" on a mounted disk. The non-disk cases are all still handled generically, but there are now clearly-labeled holes where someone could add optimized I/O strategies for tapes, sockets, etc. I've even included a number of TODO comments about what strategies I think are worth exploring, including tricks like using MTIO ioctls on tape, mmap() for disk, and nonblocking I/O for sockets and pipes. I expect any one of these is around a dozen lines of code, so should be within the reach of even fairly junior developers. Tim _______________________________________________ freebsd-hackers@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-hackers To unsubscribe, send any mail to "freebsd-hackers-unsubscr...@freebsd.org"
