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Re: [PATCH] Speed-up sprintf() family of functions.
- From: Jonathan Larmour <jifl at eCosCentric dot com>
- To: Sergei Organov <osv at javad dot com>
- Cc: ecos-patches at ecos dot sourceware dot org
- Date: Wed, 03 Jan 2007 14:50:37 +0000
- Subject: Re: [PATCH] Speed-up sprintf() family of functions.
- References: <87fyb3x070.fsf@javad.com> <459529B0.8080407@eCosCentric.com> <87wt4allsq.fsf@javad.com> <4596F7EA.4090605@eCosCentric.com> <87slewl90j.fsf@javad.com> <45987C6E.3000103@eCosCentric.com> <871wmdkv2e.fsf@javad.com>
Sergei Organov wrote:
Jonathan Larmour <jifl@eCosCentric.com> writes:
Sergei Organov wrote:
Oh yes, I know there's a lot of things I would do very differently
given the chance and the benefit of 10 more years of experience. There
are many, many places the code could be improved (or rewritten!), and
that is one.
Does anybody actually work on improving those things? From outside it
looks like kernel and libc development is stopped.
It's just a question of priorities. It's not terribly surprising that this
is lower down the list, and doesn't mean everything's wonderful now.
I think I need to experiment on this then. Hopefully this eCos part is
usually compiled without -fno-builtins?
Correct. The only times -fno-builtin is used normally is when we know
GCC is buggy in some area (and therefore usually only temporarily).
No luck. GCC (I checked 4.0.2 for ARM) just calls memcpy() when the
number of bytes to copy is not a constant. For typically small sizes, I
think direct loop is still faster, and the initial rationale still
applies.
Huh, I thought GCC was better than that. Okay, looks like you made the
right choice then!
Hmm, that kernel change did seem big enough to need one in my view. I
think someone may have dropped the ball there. We would want an
assignment for that, irrespective of this libc stdio change.
What kernel change are you talking about?
It was the kernel change I referred to earlier in the thread. This one:
2006-04-10 Sergei Organov <osv@javad.com>
Implement FIFO variant of scheduling of DSRs and make it the
default. This is reworked patch originally suggested by Stefan
Sommerfeld <sommerfeld@mikrom.com>.
Ah, those. So I was unlucky to send my patch before Stefan's has been
accepted ;) I myself consider that one trivial, being "common
knowledge", and mostly copy-pasted from pre-existing code.
Still wish to get an assignment?
Stefan doesn't have an assignment either, but I think your version is the
only one that really needs the assignment since not very much of his
original stuff remains.
Anyway, the patch is a whole is sufficient to be a copyrightable work, so
yes please, do arrange an assignment. Assuming this will come before too
long, I won't revert the patch now.
Jifl
--
--["No sense being pessimistic, it wouldn't work anyway"]-- Opinions==mine