Marco Costalba schrieb: > Currently the --prett=format prefix is looked up in a > tight loop in strbuf_expand(), if found is passed as parameter > to format_commit_item() that does another search using a > switch statement to select the proper operation according to > the kind of prefix. > > Because the switch statement is already able to discard unknown > matches we don't need the prefix lookup before to call format_commit_item() > > This patch removes an useless loop in a very fasth path, > used by, as example, by 'git log' with --pretty=format option > > Signed-off-by: Marco Costalba <mcostalba@xxxxxxxxx> > --- > > This patch is somewhat experimental and is not intended to be merged as is. > > That's what is missing: > > - Matching of multi char prefixes is not 100% reliable, as example to match > prefix "Cgreen" only the first 'C' and the third char 'e' is > checked, this could > lead to aliases in case of malformed prefixes, as example something like > "Cxxexxxx" will match the same. Well, you need to undo this optimization if you remove the loop that makes sure that only valid placeholders are passed to the callback function -- the result would be that you only move the prefixcmp() from strbuf_expand() into the callbacks. A better way to speed up strbuf_expand() may be to require the list of placeholders to be sorted, their count to be passed on and then to replace the sequential lookup with a binary search. --pretty=format currently recognizes 29 placeholders, which might be a high enough number for a more complicated search method to pay off. > marco@localhost linux-2.6]$ time git log --topo-order --no-color > --parents -z --log-size --boundary > --pretty=format:"%m%HX%PX%n%an<%ae>%n%at%n%s%n%b" HEAD > /dev/null In your special case it would be even faster to simply reorder the list with decreasing number of occurrence. Of course it's hard to guess how often a particular placeholder is used in the wild, but moving %n from next to last to first place should be a safe bet. René - To unsubscribe from this list: 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
