Date: Sun, 24 Mar 2013 13:04:24 +0100 From: magnum <john.magnum@...hmail.com> To: john-dev@...ts.openwall.com Subject: Re: inlining strzncpy - and others? On 24 Mar, 2013, at 12:20 , Solar Designer <solar@...nwall.com> wrote: > On Sun, Mar 24, 2013 at 03:16:17AM +0100, magnum wrote: >> I just replaced Dhiru's four identical instances of inlined _memmem() with a shared jtr_memmem() in misc.h (using a faster implementation while at it) and made it 'extern inlined' as per the portable model described in http://www.greenend.org.uk/rjk/tech/inline.html (i.e. with function source in misc.h instead of misc.c). > > Now we have these warnings: > > In file included from unafs.c:8:0: > misc.h: In function 'jtr_memmem': > misc.h:149:7: warning: implicit declaration of function 'memcmp' [-Wimplicit-function-declaration] Oops, fixed. It did not show in OSX. >> Do you have any opinions or wisdom on such inlining? > > It might be the way to go, but so far I avoided it in part because we > still try to support old C compilers that lack "inline". (Maybe we > should not.) We can tweak the current #if stack the same way but Jumbo contains "inline" in a lot of places anyway. >> I tested this briefly with strnzpy. The john binary grews with about 20 KB. A benchmark of raw-sha0 (using strnzpy in set_key) shows a one percent boost. That's not a lot but with slight boosts also in the rule engine, cracking modes and other parts of John it will add up to more. > > This may be a fine change to make, but regardless I think we should also > review those uses of strnzcpy() where this matters, and try to optimize > them. In rules.c, there are such uses in just 3 commands: 'x', '1', and > '2'. Of these, maybe we only care about 'x' (since '1' and '2' are for > single crack mode only, which rarely runs for long and usually has other > bottlenecks anyway; there are also uses of strnz*() in single.c). We > may try the strncat() trick for 'x' (need to benchmark it on multiple > systems/libc's). I'll do some more testing. It looks like OSX' strncat is slower than the original strnzcpy, inlined or not :-/ Not that I care much about ultimate OSX performance. magnum
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