I'm looking at doing version control of data files, potentially very large, often binary. In git, committing of large files is very slow; I have tested with a 45MB file, which takes about 1 minute to check in (on an intel core-duo 2GHz). Now, most of the time is spent in compressing the file. Would it be a good idea to change the Z_BEST_COMPRESSION flag to zlib, at least for large files? I have measured the time spent by git-commit with different flags in sha1_file.c: method time (s) object size (kB) Z_BEST_COMPRESSION 62.0 17136 Z_DEFAULT_COMPRESSION 10.4 16536 Z_BEST_SPEED 4.8 17071 In this case Z_BEST_COMPRESSION also compresses worse, but that's not the major issue: the time is. Here's a couple of other data points, measured with gzip -9, -6 and -1 (comparable to the Z_ flags above): 129MB ascii data file method time (s) object size (kB) gzip -9 158 23066 gzip -6 18 23619 gzip -1 6 32304 3MB ascii data file gzip -9 2.2 887 gzip -6 0.7 912 gzip -1 0.3 1134 So: is it a good idea to change to faster compression, at least for larger files? From my (limited) testing I would suggest using Z_BEST_COMPRESSION only for small files (perhaps <1MB?) and Z_DEFAULT_COMPRESSION/Z_BEST_SPEED for larger ones. -j. - : send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html