Bert Huijben wrote: > Ivan Zhakov wrote: >>> Author: stefan2 >>> URL: http://svn.apache.org/r1483532 >>> Log: >>> We frequently use property name constants in conjunction with hash >>> containers. Provide new wrappers around apr_hash_get and apr_hash_set >>> that accept such string constants and statically determine their size. >>> That minimizes the hash access costs. >>> >>> Mass change hash get and set calls for SVN_PROP_* constants. >> >> Is the performance gain costs code complexity? Please understand my >> correctly: it's great improve Subversion speed. I just don't like >> the idea getting code more complicated to win just several cycles. > > I can see this change making some difference when used in a tight loop in > fsfs, > but in almost every case updated here it is a single call per 'svn' (or > other tool) invocation and I don't think the added complexity and the risk > of accidentally applying it to a pointer in the future makes sense here. The > cost of a strlen on a string of a few characters certainly isn't that high. > > The IO overhead is so much larger that global changes like this in the higher > layers don't make any sense to me.
A safer and simpler design to achieve the same goal as this could be: #define svn_hash_gets(ht, key) \ svn__internal_hash_get(ht, key, strlen(key)) which works because the compiler can then optimize out the "strlen" when it is safe and possible to do so. - Julian
