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Re: [Gnu-arch-users] Slow inventories on large source trees
From: |
Tom Lord |
Subject: |
Re: [Gnu-arch-users] Slow inventories on large source trees |
Date: |
Thu, 22 Apr 2004 08:52:56 -0700 (PDT) |
> From: Aaron Bentley <address@hidden>
> Tom Lord wrote:
> > Abently, are you interested in working on this? Do you know about the
> > `cut' operator in Rx? (I.e., you don't want to combine those
> > filename_matches calls by adding parentheses to regexps. You want to
> > arrange for the final state label of the dfa to tell you which pattern
> > matched.)
> Okay, I've tried it, and it's a horrible pessimization. I don't
> understand why.
Don't panic. I need to tweak Rx.
I assume that you are passing a regmatch_t array with just one
element, right?
The cut operator can work with just a simple DFA translation of a
regexp -- and Rx supports that internally -- but it appears that
the test for whether or not that optimization applies within the posix
entry points doesn't know about `cut'. It's as if you had asked for
a full set of `regmatch_t' values --- Rx is doing lots of backtracking
work on every match.
I'll fix it early next week.
-t
Re: [Gnu-arch-users] Slow inventories on large source trees, Aaron Bentley, 2004/04/21
Re: [Gnu-arch-users] Slow inventories on large source trees, Colin Walters, 2004/04/21