Date: Tue, 9 Mar 2004 15:36:46 +1100 From: Tim Robbins <tjr@freebsd.org> To: John Birrell <jb@cimlogic.com.au> Cc: cvs-all@freebsd.org Subject: Re: cvs commit: src/lib/libc/stdio _flock_stub.c local.h Message-ID: <20040309043646.GA89072@cat.robbins.dropbear.id.au> In-Reply-To: <20040309150536.R234@freebsd3.cimlogic.com.au> References: <200403090245.i292j0a6035728@repoman.freebsd.org> <20040309032248.GA88649@cat.robbins.dropbear.id.au> <20040309143223.Q234@freebsd3.cimlogic.com.au> <20040309035532.GA88825@cat.robbins.dropbear.id.au> <20040309150536.R234@freebsd3.cimlogic.com.au>
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On Tue, Mar 09, 2004 at 03:05:36PM +1100, John Birrell wrote: > On Tue, Mar 09, 2004 at 02:55:32PM +1100, Tim Robbins wrote: > > My concern here is that we are slowing down critical paths for the > > sake of broken applications that grope around inside FILEs. Why do > > we need to support this? Which applications require it, and why? > > I'm not sure that I agree that applications are 'broken' when they > use things that are defined in the header file along with the FILE > structure itself. They are. The structure is an implementation detail, and the layout or size could change between releases, or it's definition could be moved into a libc-private header entirely. > As I said in my previous mail, if you want to improve performance, > then remove the locking code from libc completely in the single-threaded > case. That will have more benefit than checking a NULL pointer that > has to be resolved anyway in order to access the fields it points > to. Threads are useful. Supporting some phantom application you won't name that initializes its own FILE structures instead of using the correct interfaces is not terribly useful. > I think you're arguing about just a few instructions on i386. I'm arguing over a principle, and trying to stop FreeBSD getting locked into a certain arrangement of stdio internals for the sake of broken applications. Tim
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