Howard Chu writes:
oprofile shows quite a bit more overhead in 2.4's ACL processing vs 2.3's. I'm thinking of streamlining things a bit, along these lines. Any thoughts?
Only a few loose ones:
A brief look shows some deep indirection, which may be harder for compilers to optimize due to possible aliasing among intervening writes. Maybe you should help by unpacking some more common expressions into local variables.
Beyond that, seeing "ACL optimization" I think "bytecodes". acl.c has many if/switch statements just to find out what an acl expression is doing. A flat 'switch(*bytecode++)' implementation should help, though I haven't looked closely and I'm not about to try anytime soon.
Of course, that points to a slapd.conf 'access' language which maps more directly to the bytecodes, or compiler techniques like common subexpression elimination and lazy evaluation... a mini Haskell implementation in slapd, yay:-)